

Class 

Book 





ILLINOIS 

n 

STATE GEOLOGICAL SURVEY. 


BULLETIN No. 11. 


Physical Features of the 
Des Plaines Valley 


BY 

\ 

James Walter Gold th wait 




Urbana 

University of Illinois 
1909 


I 





SPRINGFIELD, ILL., 

Illinois State Journal Co., State Printers 

1909 


D, Of a 


N . 4. 


1910 , 




V * 

c 


STATE GEOLOGICAL COMMISSION. 


Governor C. S. Deneen, Chairman . 

Professor T. C. Chamberlin, Vice-Chairman. 
President Edmund J. James, Secretary. 


PI. Foster Bain, Director. 

R. D. Salisbury, Consulting Geologist , in charge 
of Educational Bulletins. 




of the preparation 




TABLE OF CONTENTS. 


Page. 


List of illustrations 

Letter of transmittal 

Chapter I. Geography and history of the Des Plaines river 

Introduction 

The Des Plaines basin 

History of the Chicago portage and the canals 

Chapter II. The structure of the bed rock : 

Deposition of Paleozoic sediments 

Nature and age of the rocks 

The Cambrian period 

The Ordovician period 

The Silurian period 

The Devonian period 

The close of sedimentation ' 

Warping, jointing, and faulting of the rocks 

Folds 

■ Joints 

Faults 

Chapter III. The concealed surface of the bed rock 

Significance of the buried topography 

Pre-glacial denudation 

Deductions from the driftless area 

The pre-glacial topography 

The development of underground drainage 

Glaciation 

The glacial period 

The smoothing and striating of the rock surface 

The burial of the rock surface with drift 

The buried topography 

Chapter IV. The glacial and interglacial deposits 

The distribution and surface form of the drift 

Thickness of the drift 

Complexity of the drift 

The two kinds of drift 

The ice-laid drift or till 

The stratified drift 

The Joliet conglomerate 

Chapter V. Physiographic history of the lower Des Plaines river 

General description 

Deposition of the early Wisconsin drift 

The early Wisconsin moraines .*. 

The lake in the Morris basin 

Deposition of the late Wisconsin drift 

The Minooka till ridge 

The Valparaiso morainic system and its outwash 

Excavation by the outlet of Lake Chicago 

Glenwood stage. Excavation of a trench in the valley train 

Calumet stage. The Lockport sill 

Toleston and later stages. Abandonment of the outlet and substitution of the Des 

Plaines river 

Erosion by tributaries 

Fraction run 

Long run and other tributaries above the sill 

Spring creek and Hickory creek 

Sugar creek 

Reed’s woods ravine 

Alluvial fans and cones • 


vii 

ix 

1 

1 

3 

6 

10 

10 

10 

11 

12 

14 

17 

19 

19 

19 

20 
21 
23 

23 

24 
24 

24 

25 

26 
26 

29 

30 

31 
33 

33 

34 

35 

35 

36 
38 
42 
46 

46 

47 

47 

48 
48 

48 

49 
52 
52 

54 

55 
57 
57 
59 

59 

60 
60 
64 


VI 


Table iof contents — Concluded. 

Page. 

Chapter VI. Physiographic history of the upper Des Plaines river 66 

Deposition of the till ridges 66 

Lake Chicago 67 

Glen wood stage 67 

The Oak Park spit 67 

Shoreline between Maywood and Mt. Forest 73 

Calumet stage 74 

Emergence of the door of Des Plaines bay 74 

The Calumet shoreline 75 

Toleston stage 78 

Extension of the Des Plaines river near Riverside 78 

Renewed trenching of the valley : 79 

The Toleston shoreline ’ 79 

Subsequent changes leading to formation of Lake Michigan 81 

Excavation of the valley 81 

Development of tributaries 86 

Chapter VII. Floods on the Des Plaines river 88 

The upper river 88 

The lower river 91 

Appendix. Suggestions for field trips 94 


VII 


LIST OF ILLUSTRATIONS. 


Plates. 

Page. 

1. Fossils from the Niagara formation 16 

2. (a) Lock on the Illinois- Michigan canal above Joliet 22 

(b) Fault in the wall of the Sugar creek gorge 22 

3. Pebbles from the drift 36 

4. (a) Stratified drift at Overholser’s pit, Joliet 40 

(b) Exposure of Joliet conglomerate near Spring creek 40 

5. (a) Outwash terrace on Spring creek 42 

(b) Fraction run above Dellwood park 42 

6. Map of the gorge of Sugar creek 60 

7. Map of the ravine in Reed’s woods 62 

8. (a) Young gully near Reed’s woods 76 

(b) Calumet beach ridge at Summit 76 

9. Effects of a recent flood on Hickory creek 92 


Figures. 

1. Map of the Des Plaines basin 2 

2. Section through the rock in a deep well at Lockport 10 

3. North America in Potsdam and in Trenton time 13 

4. North America in Niagara and in later Devonian time 15 

5. Map of the North American ice sheet 26 

6. Map of the moraines in Illinois „ 28 

7. Sections of residual soil and of drift 29 

8. Block diagram— The ice sheet and the west ridge of the Valparaiso morainic sys- 

tem 40 

9. Block diagram— The ice sheet and the Valparaiso moraine 41 

10. Map of the lower Des Plaines river 47 

11. Maps showing two stages of Lakes Chicago and Maumee 53 

12. Diagram to illustrate ‘ stoping” in the Chicago outlet 55 

13. Block diagram— Effect of recession of falls on tributaries 58 

14. Block diagram— A crooked gully 62 

15. Block diagram— A meandering gully 63 

16. Map of part of Lake Chicago. Glenwood stage 68 

17. Map of the district about Oak Park and Maywood 70 

18. Map of part of Lake Chicago. Calumet stage 75 

19. Map of the district between Riverside and Summit 77 

20. Map of part of Lake Chicago. Toleston stage 80 

21. Diagram showing the development of a straight-walled, fiat- floored valley 84 


% 




IX 


LETTER OF TRANSMITTAL. 


State Geological Survey, 

University of Illinois, 

Urban a, March 22, 1909. 

* 

Governor C. S. Deneen , Chairman , and Members of the Geological Com- 
mission : 

Gentlemen — I submit herewith a report on the Physical Features of 
the Des Plaines Valley with the recommendation that it be published as 
Bulletin 11 of the Survey. This forms the second of the “Educational 
Bulletins” of the Survey being prepared under the general direction of 
P. D. Salisbury, Consulting Geologist of the Survey. The author, Dr. J. 
W. Goldthwait, now of Dartmouth College, prepared this while connected 
with Northwestern University. Into it he has put the accumulated ex- 
perience of several years’ teaching during which the Des Plaines Valley 
was explored and studied as a field for illustration of the common prin- 
ciples of physiography. While, therefore, the report will be of particular 
interest to people living in the vicinity, it will afford excellent illustrative 
material wherever rivers and their valleys are being studied. The large 
demand for the preceding bulletin of this series (Bulletin 7) indicates 
a very widespread and live interest in the subject of physical geography 
among teachers and laymen. An intelligent insight into one’s environ- 
ment is the desire of every normal person and it is felt that these little 
bulletins serve a very real need even of those not concerned with teach- 
ing. Dr. Goldthwait’s studies of the development and history of this, a 
t}fpical stream of our region, with his special notes on its floods, have 
also a very direct and practical value in view of the area of land subject 
to overflow and the need for regulation of the stream. 

In the preparation of the text, and illustrations free use has been made 
of earlier publications and the author desires that acknowledgments be 
made especially to Messrs. Frank Leverett and W. C. Allen of the U. 
S. Geological Survey, and Mr. Lyman E. Cooley, Civil Engineer, of Chi- 
cago. A copy of the well executed map of Cook county, drawn for the 
Sanitary District of Chicago, was furnished the author, through the 
courtesy of the Chief Engineer, Mr. Isham Randolph, and has been of 
great value. Small portions of this map have been copied in reduced 
form in Figs. 17 and 19. Mr. J. W. Ferris of Joliet contributed useful 
information concerning the fossils of that vicitnity. To Mr. J. M. Large, 
instructor in physical geography in the Joliet township high school, the 
— 2b G 


X 


writer is indebted for a contour map of the ravine in Reed's woods. This 
map was extended and redrawn to form Plate 7 by Mr. 1). F. Higgins, 
who also prepared a contour map of the gorge of Sugar creek (Plate G) 
and aided greatly in the preparing of other illustrations. Special ac- 
knowledgment is due to Mr. Charles F. Decker for efficient help in 
the field, and to Professor R. D. Salisbury for kindly yet most thorough 
criticism. 

The Survey is under great obligations to these gentlemen, and to Dr. 
Goldthwait for the preparation of the report, all of which it is a pleasure 
to acknowledge. Very respectfully, 

H. Foster Bain. 

Director. 


/ 


PHYSICAL FEATURES OF THE DES PLAINES 

VALLEY. 


(By James Walter Goldthwait.) 


CHAPTER I. 

GEOGRAPHY AND HISTORY OF THE DES PLAINES RIVER. 

INTRODUCTION. 

The Des Plaines valley is one of peculiar interest geologically and his- 
torically. The lower portion of the valley, southwest of Chicago, was 
once occupied by a great river, the outlet of an early Lake Michigan. 
The divide over which the lake once spilled to the Des Plaines, now the 
continental divide between the Laurentian lakes and the gulf, is only 
about ten feet above the present lake. So low and flat is this divide that 
before the construction of the Illinois-Michigan canal it was covered by 
the spring freshets of the upper Des Plaines, and afforded the early 
French explorers an easy and continuous canoe route from the lakes 
to the Mississippi. The Chicago pass is fully 1T5 feet lower than the 
next lowest pass in the St. Lawrence-Mississippi divide, at Ft. Wayne, 
Indiana. No wonder that the idea of an artificial channel near Chicago, 
to join the lakes with the Mississippi, was conceived by Louis Joliet, 
one of the first men to cross the divide. The plan thus early suggested 
was at length realized in 1848, when, after years of delay, the Illinois- 
Michigan canal was completed and opened to traffic. Again, when the 
city of Chicago had outgrown its drainage facilities, the valley was re- 
sorted to for the great sanitary canal of Chicago. Rich in historic as- 
sociations, and inevitably connected with the great metropolis, the Des 
Plaines valley is destined to become of the highest commercial import- 
ance; for it now awaits the construction of a deep waterway that shall 
conduct lake vessels across Illinois to the Mississippi. 

Thus the valley of the lower Des Plaines possesses in a peculiar sense 
elements of a strictly geograjfliic value. In its physical features lie the 
reasons for its early discovery and exploration, its present industrial 
advantages, and its future development. 

It is not within the province of this report to dwell unon the geog- 
raphy of the valley — the relationships between the physical features and 
the historical and industrial conditions — however interesting such a 


2 


THE DES PLAINES VALLEY 


[BULL. NO. 11 


x Outline of D espial nes and 

l Dupage basins 

Outline of glacial Lake Chicago 
/ and Chicago Outlet. 

£4 ff/hooka Till ftidge. 

Lake -border morainic system. 

;•*> Valparaiso morainic system. 

SCALE. 



O FyU del 


Fig. 1. Map of the Des Plaines basin and vicinity. The distribution of 
glacial drift is taken from Leverett’s map in Monograph 38, U. S. Geol. Surv. (in 
Illinois), and from Alden’s map in Prof. Paper 34, U. S. Geol. Surv. (in Wisconsin). 


GOLDTHYVAIT.] 


GEOGRAPHY AND HISTORY. 


a 


story may be. Bather is it the purpose here to describe the physical 
features and to explain the manner in which they have been developed. 
The valley abounds in phenomena which would be of interest to many 
persons living near by, and of especial use to students of physical geog- 
raphy and geology in the schools. Before presenting this material, it 
will not be out of place to take a general view of the river basin and the 
Des Plaines river, and to outline briefly its history. 

THE DES PLAINES BASIN. 

The long narrow basin of the Des Plaines river (see Fig. 1.) lies only 
a few miles west of Lake Michigan, in the northeast corner of Illinois. 
From northern Kenosha county in Wisconsin southward through Lake, 
Cook, DuPage and Will counties in Illinois, the basin has a length of 
ninety miles. Its width, however, is never over twenty-five miles, and 
for a large part of the distance is less than fifteen. Its area is about 
1,400 square miles. 

The northern portion of this basin is narrow, and is drained almost 
wholly by the trunk river and a single tributary, Salt creek. Its area 
(above Summit) is about 634 square miles. The southern portion is 
wider and more complex, for it includes the north-south basin of the 
Du Page river, the largest tributary of the Des Plaines, and several 
rather long creeks from the east. A few miles below the mouth of the 
DuPage, the Des Plaines unites with the Kankakee to form the Illinois 
river. 

The elongated form of the Des Plaines basin is largely, if not wholly 
dependent on the disposition of glacial drift. At the close of the glaciai 
period, when the district finally emerged from beneath the waning ice 
sheet, the bed rock had been concealed by an irregular blanket of loose 
earthy material or “drift,” deposited in part by the glacier itself and 
in part by the waters that came from it. Conspicuous among the newly 
built surface features was a broad U-shaped belt of rolling ground, stand- 
ing a little above its surroundings, and encircling the south end of Lake 
Michigan through Illinois, Indiana and Michigan. This belt is known 
as the Valparaiso moraine. The manner in which it was built up around 
the edge of a lobe or tongue of ice which lingered in the lake basin will 
be explained in a later chapter. It is enough here to note that the great 
moraine is crossed obliquely by the Des Plaines river between Summit 
and Joliet, and that from its slopes comes a large part of the water 
discharged by the river. The Valparaiso morainic belt is, in fact, a 
system of parallel ridges; (1) a central ridge which makes up the main 
body of the moraine; (2) an outer ridge, lower or narrower, which 
divides the Du Page basin from the Des Plaines proper, north of Joliet, 
and which for several miles southwest of Joliet is separated from the 
main moraine by a crescent-shaped plain and (3) an’ inner ridge, lying 
east of the central belt, and separated from it by the basin of Salt Creek. 

Just outside the Valparaiso morainic system is another border mor- 
aine, known as the Minooka till ridge, which forms the west boundary 
of the Du Page basin, and ends interruptedly near the junction of the 


\ 


4 THE DES PLAINES VALLEY. [bull. no. 11 

Des Plaines and Kankakee. On the inside of the Valparaiso moraine, 
near Lake Michigan, is a group of till ridges called the “lake-border 
morainic system.” Southwest of Chicago these are absent; but near 
Oak Park one of them appears, and runs northward into Wisconsin,, 
being joined on the way by others of the system whose south ends are at 
Winnetka and Northfield. Since these till ridges both branch and 
coalesce as they run northward, the number of distinct morainic lines at 
different points is variable. In northern Cook county it is three, in Lake 
county two, and in Kenosha county, Wisconsin five. 

Surrounding the city of Chicago, between the curving Valparaiso 
moraine and the lake, is the crescent-shaped Chicago plain. It is the 
smooth floor of an extinct Lake Chicago, which for a long time occupied 
the space between the morainic ridge and the melting ice lobe. Its 
former border is marked by abandoned beach ridges and wave-cut banks, 
and its surface is somewhat diversified by similar shore forms built at 
lower levels as the lake fell from its original height down to the present 
stage. On its north side the lake plain finds extension in a flat depres- 
sion which separates the Valparaiso moraine from the west till ridge, 
and constitutes the present valley of the upper Les Plaines. 

Let us now follow the Des Plaines from its source among the till 
ridges of Wisconsin southward along the shallow inter-morainic depres- 
sions across a corner of the Chicago plain, and on through the Val- 
paraiso moraine hy way of the old outlet. 


THE DES PLAINES RIVER. 

The Des Plaines issues from a flat swamp, or slough, near the bound- 
ary of Racine and Kenosha counties, Wisconsin, where drainage is so 
imperfect that in wet weather part of the marsh discharges northward 
to Root river and part southward to the Des Plaines. From this ill- 
defined divide the little stream runs south along the depression which 
separates the two westernmost of the lake-border till ridges, gathering 
drainage from other creeks among the morainic hollows, turning to run 
eastward for a few miles in Kenosha county, then resuming a southerly 
course and entering Illinois between the two till ridges .which at that 
point compose the whole lake-border system. West of Waukegan (near 
Gurnee station) the river passes through the west ridge; and thence south- 
ward past Liberty ville, Wheeling, Franklin Park and Maywood, it fol- 
lows the broad inter-morainic basin immediately east of the Valparaiso 
moraine. Entering the Chicago plain by way of this broad pass, which 
is in itself an arm of the lake-plain nearly shut off by a long sand spit at 
Oak Park, the river winds around a beach ridge at Riverside, swinging 
as:ain eastward around a rock elevation at Lyons. 

o J 

In the distance of sixty miles from the head of the Des Plaines to the 
Riverside dam, the ‘river falls ninety feet, or at an average rate of l 1 /? 
feet per mile. The portion in Lake county has a moderately uneven 
grade, for the river flows through a. series of flat, marshy stretches separ- 
ated by more pronounced slopes. Through Cook county its fall is much 
more uniform, since it has entrenched itself in a valley, and built a 


COLDTHWAIT.] 


GEOGRAPHY AND HISTORY. 


5 


well-graded flood plain. From Riverside down-stream for three miles, 
the Des Plaines descends fourteen feet on the exposed ledges, or about 
five feet per mile, to the Ogden dam. At this point it lies within ten 
miles of Lake Michigan, and is less than twelve feet above.it. For a de- 
tailed map t>f this vicinity, see Fig. 19. 

Here, then, near Summit, is the divide between the lakes and the 
Gulf, the St. Lawrence and the Mississippi. In time of flood a large 
portion of the Desplaines discharges over the dam and through a ditch 
to the Chicago river and the lake, while the remainder follows the lower 
JDes Plaines down to the Illinois and Mississippi rivers. This double 
discharge was operative under natural conditions before the Ogden dam 
was built. The natural divide was five miles farther east, near Kedzie 
avenue, at the east end of a great swampy tract, known as Mud lake. So 
flat is the plain at this point that the escape of the Des Plaines from 
the lake plain westward through the deep notch in the moraine seems 
highly accidental. 

From Summit it makes for the head of the abandoned channel of the 
“Chicago outlet" where the waters of Lake Chicago once poured across 
the moraine toward the Illinois valley. With uncertain course, the river 
runs for a long distance on the flat channel floor. This stretch between 
Summit and Lemont is known as the “12-mile level.” Since the con- 
struction of the sanitary canal, the Des Plaines is confined to an artificial 
channel by earthworks. Approaching Lemont, the river finds bed rock 
rising to the level of the valley floor, and still higher on either side in 
rock bluffs. Hear the left bank of the Des Plaines and parallel to it 
down the outlet, run the Illinois-Michigan canal and the Chicago drain- 
age canal. Both of them are largely cut in solid limestone. 

Beyond Lemont the rock declines again to about the level of the valley 
floor, and the channel is cut through the thick till structure of the 
moraine. Bending southward, the river runs past Borneo ; and now there 
appear at the top of its bluffs, terrace remnants of an old outwash plain 
or valley train — the original filling of the valley, deeply trenched by 
the outlet. At Borneo the Des Plaines begins to descend a long series of 
shallow rapids, which lower it eighty feet in the ten miles to Joliet pool. 
At Lockport, on the old canal, and farther down, near Joliet, are three 
locks, made necessary by the rapids. One of them is pictured in Plate 2. 
Here the bed rock rises some thirty or forty feet above the floor in 
bluffs on both sides of the valley, forming a flat rock terrace twenty feet 
lower than the fragments of the outwash plain. These two terraces, the 
one of gravel and sand of the outwash, and the other of rock, mark 
important steps in the history of the river, and of lake Chicago of which 
it was the outlet. At Joliet, the river is confined artificially, passing 
through the west side of the city. A single dam crosses it at Jackson 
street. Below Joliet the descent of the river is steep for two or three 
miles to Brandon’s bridge, where it broadens, forming Joliet pool. 

This pool, otherwise known as “Lake Joliet,” occupies a broad, shal- 
low depression (ranging to ten feet in depth) in the floor of the old 
outlet. It extends five miles down the valley, below Brandon’s bridge, 
allowing the river no perceptible fall in that distance. The level of the 


6 


THE DES PLAINES VALLEY. 


[BULL. NO. 11 


river here is about seventy-six feet below Lake Michigan. The pool is 
probably due to a deepening of the floor of the ancient river, where it 
jiassed from the hard Niagara limestone out on to the weaker limestones 
and shales of the Cincinnati formation. 

Below Joliet pool, the slope of the river is again moderate for three 
miles. Just beyond the mouth of the Du Page river another pool — 
“Lake Du Page” — is entered. This is ninety feet below Lake Michigan, 
and extends three miles down the valley. Half a mile below it, the Des 
Plaines joins the Kankakee, at the head of the Illinois river. 

HISTORY OF THE CHICAGO PORTAGE AND THE CANALS. 

The divide between the Des Plaines river and Lake Michigan stands 
only 592 feet above the sea — less than twelve feet above the present lake. 
It is a part of the floor of the extinct Lake Chicago which is so flat as 
to show no slope to the eye. Before the natural drainage of the district 
was disturbed by trenches and canals, the divide was a broad, swampy 
tract, called Mud lake; a long slough west of Kedzie avenue which in 
time of flood led a part of the water from the Des Plaines river east- 
ward to the west branch of the Chicago river and Lake Michigan. In- 
deed, this slough may at no very remote time have carried the entire dis- 
charge of the Des Plaines river. It was evidently a familiar path for the 
Indians, who in time of flood might paddle their canoes continuously 
from the Chicago to the Des Plaines. 

An entertaining and instructive account of the early exploration of 
this region by the French traders and missionaries is to be found in 
Parkmairs “LaSalle and the Discovery of the Great West.” In 1671, 
LaSalle started out in search of the Mississippi. Sailing through Lakes 
Erie and Huron, and entering Lake Michigan, he proceeded southward 
past the head of Green bay. Turning towards the west at a “tres-beau- 
havre,” which Parkman thinks may have been the mouth of the Chi- 
cago river, he crossed to a river that flows westward — doubtless the Illi- 
nois. The fact that LaSalle chose the Chicago portage on a later ex- 
pedition, in 1682, lends strength to the belief that this was his route 
in 1671. If so, he was the first white man to cross the divide at Chi- 
cago. 

In 1673, the intrepid explorer Joliet and his Jesuit companion Mar- 
cjuette, returning from their successful voyage of discovery on the Missis- 
sippi, followed up the Des Plaines and across the portage. In August, 
1674, Joliet, in a letter to Father Dablon, 1 states that “by cutting half 
of a league of prairie" between the “Lake of Illinois” (Lake Michigan) 
and the “Saint Louis river” (the Illinois) an easy boat route would be 
made between the lakes and Florida. In 1673-4, Marquette, on his way 
from Green Bay to the Mississippi, where he hoped to found a new 
mission, was forced by illness to spend the winter at Chicago. With 
his two French comrades, he built a cabin beside the west fork of the 
south branch of Chicago river, near the present Eobey street v On the 
last, day of March he was driven away by a, spring freshet and ice 


l Quoted by L. E. Cooley, in “The Lakes and Gulf Waterway” — report by the 
Internal Improvement Commission of Illinois to the Governor, Feb. 1907, p. 3. 


GOLDTHWAIT.j 


GEOGRAPHY AND HISTORY. 


7 


gorges on the Des Plaines, which flooded the low ground in that vicinity. 
He crossed the divide on March 31st, in canoes, and went down the 
Illinois river as far as Utica. Compelled by broken health to return 
just as his hopes were being realized, Marquette died on his way up the 
east side of Lake Michigan. 

In the winter of 1679-1680, LaSalle crossed the neighboring divide 
at the St. Joseph river, and went down the Kankakee and Illinois rivers 
to Peoria. Returning a few months later, he followed up the Des Plaines 
as far as Joliet, but chose thence an overland route eastward — a more 
direct course for Port Miami. Again in January, 1682, LaSalle, ac- 
companied by Priar Hennepin, by Tonty, his Italian lieutenant, and by 
some fifty Prenchmen and Indians, journeyed from “Checaugou” across 
the divide and down the frozen Des Plaines on sledges, to Peoria. There 
they found open water, and, launching their canoes, floated down the 
Illinois and Mississippi nearly to the Gulf. Returning late the same 
year, LaSalle established Port Saint Louis at Starved Rock, opposite 
Utica, remaining in that vicinity a year and then returning to Prance. 

LaSalle’s attempt to find the Mississippi from the Gulf of Mexico in 
1687 failed. He was assassinated in Texas by members of his party. The 
fugitives, together with Tonty (who had been in charge of Port Saint 
Louis) made their way across the Chicago portage in 1688, en route to 
France. 

Messrs. R. Graham and Joseph Phillips are quoted by Mr. Cooley in 
his recent report 1 to have written in 1819 the following: “The route by 
Chicago as followed by the French since their discovery of the Illinois 
presents at one season of the year an uninterrupted boat communication 
of six to eight tons burden between the Mississippi and the Michigan - 
lake ; at another season a portage of two miles ; at another a p.ortage of 
seven miles, from the bend of the Plein (Des Plaines) to the arm of the 
lake; and at another a portage of fifty miles from the mouth of the 
Plein to the lake, over which there is a well beaten wagon road. Boats 
and other loads are hauled by oxen and vehicles kept for that purpose by 
French settlers at Chicago.” 

Since the opening of the Illinois-Michigan canal, in 1848, when the 
Mud lake slough was first tapped and drained by a ditch, several similar 
trenches have been excavated, at public and private expense, and a dam 
erected west of the slough, close to the Des Plaines, as a substitute for 
the ridge of the divide. (See Fig. 19). Still, in time of flood, the 
Des Plaines overflows the Ogden dam, and the slough is filled with 
water. 

The project of a ship canal across the Chicago portage was laid before 
congress by Albert Gallatin, in his famous report of 1808, on means of 
internal communication. A few years later it was recommended to 
congress in a bill along with the Erie canal. While the latter, thanks 
to the perseverance of DeWitt Clinton, was soon undertaken, and finished 
in 1825 — a “ditch” running 360 miles across Hew York state — the 
Illinois-Michigan canal was long delayed. Although it was commenced 


l Op. cit., p. 5. 


s 


THE DES PLAINES VALLEY. 


[BULL. NO. 11 


in 1836, it was not until 1848, when railways were already replacing 
canals elsewhere, that the Illinois-Michigan canal was finished, with 
the summit level across the Chicago divide eight feet above low water 
mark of the lake. Water was supplied by “the feeder” through the 
“sag” (a broad valley tributary to the Des Plaines above Lemont), and 
in times of low water by lift wheels at Bridgeport. Its length, down 
to its termination at LaSalle, was nearly a hundred miles; its vertical 
descent almost 150 feet. Two locks were required near Lockport, and 
two at Joliet. The canal was made six feet deep, sixty feet wide at the 
surface and thirty-six feet at the bottom in earth, and forty-eight feet 
wide in rock. It cost the State and the. city of Chicago about $10,000,- 
000.00, only one-tenth the cost of the Erie canal; and two-thirds of this 
was paid by a land grant. 1 

The failure of the government to properly dredge the Illinois river 
below LaSalle greatly limited the development of the canal. While 
the Erie canal, profiting by the improvement of the Hudson, was a 
vitalizing artery of commerce for the city of Hew York, the Illinois 
canal, too small for lake boats and leading to a barely navigable river, 
contributed only in a moderate degree to the growth of Chicago. In 
1885 it was estimated that the canal had saved the people of Illinois 
$180,000,000.00 in freight charges. 2 

The plan of supplying the canal from Lake Michigan — restoring in 
miniature the ancient outlet of Lake Chicago, was not carried out until 
1871, when the city of Chicago cut down the summit level for sanitary 
purposes. For the first time in probably several thousand years, waters 
flowed out from Lake Michigan to the Mississippi. Meanwhile, the 
federal and State governments spent a considerable amount of money 
in constructing locks and dams along the lower Illinois. Agitation of 
plans for a deep waterway from the lakes to the gulf, continually re- 
curring, availed little against conservative reports and recommendations 
of the United States army engineers. 

The extraordinarily rapid growth of Chicago soon made the Illinois- 
Michigan canal inadequate for the discharge of its sewage. Early in 
August, 1885, a heavy flood on the Des Plaines swept the sewage of the 
city out into the lake; and the pollution of the city water supply was 
-so intolerable that steps were at once taken to remedy the drainage con- 
ditions. Plans were gradually formed for a new sanitarv canal. The 
construction and operation of this channel was delegated to a “Sanitary 
District of Chicago,” under an act adopted at the November election, 
1889, the district being organized the following January. 

The work of excavating the drainage canal was begun in September, 
1892, and finished in January, 1900. Its length from the west fork 
of the Chicago river at Piobey street to the controlling works at Lock- 
port was twenty-eight miles. Of this a little more than half (the 
fifteen miles between Willow springs and Lockport) was cut through 
rock. Above Willow springs the channel was sunk wholly in unconsoli- 


1 Statement by L. E. Cooley. “The Lakes and Gulf Waterway, as Related to 

the Chicago Sanitary Problem,” pp. 4 and 7. 1S91. 

2 Li. E. Cooley’s report of 1907, p. S. 


GOLDTH WAIT . ] 


GEOGRAPHY AND HISTORY. 


9 


dated beds, mainly glacial drift. The depth of the canal is twenty-four 
feet, its bottom width, where in earth, 202 feet, and where in rock, 160 
feet. The declivity is 1 to 40,000 in the section above Willow springs, 
and 1 to 20,000 below, giving a total fall from the head at Bridgeport 
to the controlling works at Lockport of about 5% feet. The Des Plaines 
river was diverted from its natural channel by embankments between 
Summit and Lockport. Several large bridges were built, and necessary 
improvements made on the river below the controlling works. The dis- 
charge of sewage down the new channel and eventually out to the Mis- 
sissippi past St. Louis aroused bitter feeling in that city. On the same 
day that the canal was formally opened a bill of complaint was filed 
in the U. S. Supreme Court in the case of “State of Missouri against 
State of Illinois and Sanitary District of Chicago," asking that the dis- 
charge of sewage be stopped. After six years of expensive legal battles 
find investigations by experts, the complaint was dismissed. 

Now that the sanitary canal is again nearly outgrown by the great 
cit}r, repeated efforts are being made to obtain the privilege to enlarge 
it and to divert a larger volume of water from Lake Michigan, thus in- 
suring the proper dilution of the sewage. The extension of the channel 
to Joliet and LaSalle, and the improvement of the Illinois river so as to 
give- a deep waterway across the State to the Mississippi and thus to the 
gulf, even if not immediately possible, is none-the-less inevitable. Such 
an attainment will fittingly express the enterprise and foresight of the 
twentieth century. The project of Louis Joliet of an unbroken path 
for boats from the lakes to Florida will at length be fully realized, and 
the Des Plaines valley will become one of the great avenues of inland 
navigation. 


10 


THE DES PLAINES VALLEY. 


[BULL. NO. 11 


CHAPTER II. 


THE STRUCTURE OF THE BED ROCK. 


DEPOSITION OF PALEOZOIC SEDIMENTS. 


Nature and Age of the Rocks . — Beneath the loose, unconsplidated de- 
posits, chiefly glacial “drift,” which cover most of the surface of the 
ground in this region, is a firm rock foundation. This bed-rock struc- 


500 


+ 250 - 


SEA LEVEL 


• 250 - 


-500 


- 750 - 


- 1 ooo -r 


-1250 


E XT T~ 

Li I — L 

I O i 




i i i I 


I TT 


-L I 


m . i 


> 




t~ t 


\ i i m 


l 


i i \ \ i 


T I ' i ~ r-r 





Feet. 


Niagara limestone 220+ 

Cincinnati shale 110+ 

Trenton limestone 300+ 


St. Peters sandstone 210 


Lower Magnesian limestone, including red marl and 
shale 395 


Potsdam sandstone, including some red marl and shale.. 686+ 


Fig. 2. Section of rocks in a deep well at Lockport. (After Alden, U. S. 
Geol. Surv. ) 


GOLDTHWAIT.] ' STRUCTURE OF BED ROCK. 11 

ture consists of an unknown thickness of great stratified formations — 
limestones, shales and sandstones of comparatively remote age. The 
formations are nearly horizontal in position, resting one upon the other. 
Their bedded or “stratified” structure, fragmental composition (in part), 
and the marine shells which are fossilized in them, indicate clearly that 
the rocks accumulated as successive sheets of sediment on the sea floor, 
spread out in the order of their position, the oldest at the bottom. The 
consolidation of the original clays, sands, and calcareous muds into 
firm, compact rock is due largely to the cementing action of percolating 
waters, which deposited mineral substances in the interstices of the 
strata. Consolidation is favored, if not actually affected, also, by the 
pressure of overlying sediments, including great thicknesses of strata 
which formerly buried these but have been wholly removed from the 
region by erosion. From their relation to overlying and underlying rocks 
in other regions, as well as from the relics of animal life they contain, 
these formations are known to belong to early geologic periods, the 
Cambrian, Ordovician and Silurian. These constitute the first three 
divisions of the Paleozoic- era. 

The Cambrian Period . — During these early periods, the central part 
of North America, including the Great Lake region, was occupied by 
an interior epicontinental (on the continent) sea. The depth and extent 
of this sea fluctuated repeatedly. The rising of it, at certain times, with 
respect to the neighboring lands, is believed to have been due largely to 
the fact that the lands, exposed to the disintegrating and denuding forces 
of the atmosphere and running water, were being reduced to lowlands, 
while the rock waste thus stripped from them was being deposited in 
the sea, partly filling the ocean basins. The waters thus displaced would 
rise, and even though the actual change of level might be slight, it 
would be enough to cause the sea to transgress far over the lands, 
because of their greatly reduced condition. Changes in relation of land 
and sea were doubtless inspired also by warpings and dislocations of por- 
tions of the earth's “crust,” While it is clear that such warpings have 
occurred, in abundance, inasmuch as rocks which must once have been 
essentially horizontal on the sea floor are now found far and wide over 
the lands, in a great variety of warped and folded attitudes, we cannot 
tell witli certainty the reason for the deformations. It may be that 
gravity, or the tendency of the earth's mass to crowd radially toward the 
center, finds temporary and partial relief in the sinking in or caving of 
portions of the earth which are excessively heavy (the ocean floors) or 
less firmly supported from beneath than the surrounding, structure. It 
• may be, also, that the earth has been cooling off for ages, and while cool- 
ing, contracting; that along with this contraction it has been shrinking, 
and the more rigid outer portion or “shell” has accommodated itself to 
the shrinking “nucleus” by warping or wrinkling. 

Some such processes as these caused the epicontinental sea, during the 
Cambrian period, to creep gradually up over the low interior of North 
America, expanding on all sides, until by the end of the period, all the 
central portion of the continent and most of the western and north- 
western portions were submerged. (See Fig. 3). An extensive highland 
belt, “Appalachia,” separated this interior sea from the Atlantic on the 


12 


THE DES PLAINES VALLEY. 


[BULL. NO. 11 


east, and long, discontinuous mountain belts in the far west and north- 
west, separated it from the Pacific. On the north, a great V-shaped 
land area in Canada, “Laurentia,” formed at that time the main part of 
the land of the North American continent. Two large highlands, out- 
liers of the Laurentia land, perhaps escaped submergence; one in the 
Adirondack region of northern New York, and the other in the high- 
lands of northern Wisconsin. Around their subsiding borders were spread 
out in late Cambrian time extensive deposits of sand. From the Wis- 
consin highland region the sand reached southward on the sea floor well 
into Illinois, and now constitutes the Potsdam sandstone, which is pene- 
trated by a few deep wells in and about Chicago (See Fig. 2). 

The Ordovician Period . — During the next geologic period, the Ordo- 
vician, the interior sea continued to expand, though local and tempor- 
ary oscillations of its floor and its shores kept changing its outline. In 
northern Illinois, a change from sandy sediments to sandy limestones 
and finally to pure, fine-grained limestones as the Ordovician period 
progressed indicates that the surrounding land areas suffered great reduc- 
tion under the destructive action of atmosphere and erosion, so that 
during middle and late Ordovician the waters of the interior sea were 
no longer clouded by river-borne sediment, and the deposits made were 
limited almost wholly to shells, corals, and other organic remains. The 
early Ordovician sediments are the Lower Magnesian limestone and the 
St. Peter’s sandstone. Both are encountered by wells (See Fig. 2) . Above 
them is the Trenton limestone, containing an abundance of fossils, which 
indicate that the water, while relatively clear, was shallow and rather 
warm. The sea floor was peopled by colonies of lime-secreting animals, 
such as corals, brachipods, trilobites, and others whose peculiarities may 
properly be left for fuller consideration in connection with the Niagara 
limestone, since that is the only rock exposed to any extent in the Des 
Plaines valley district. 

Toward the close of the Ordovician period, the Trenton limestone de- 
posits were buried by a great sheet of mud, over one hundred feet thick, 
which has since been consolidated into the Hudson river or Cincinnati 
shale. By the time the mud of this formation was deposited the interior 
sea had begun to shrink, and the surrounding land to emerge, exposing 
broad coastal plains, from which and across which sediment was washed 
into the sea. 

Geographic changes of large extent now occurred. Intense deforma- 
tions in eastern New York added to the width of the Appalachian moun- 
tain belt, while in the Mississippi valley region there was a very exten- 
sive emergence of land, with, however, little or no deformation of the 
rocks. The interior sea shrank to small proportions and marine life 
became seriously restricted. Many species of animals were forced to . 
migrate to deeper parts of the seas, and many were exterminated. These 
parallel changes of the geography and the fauna are the reasons for 
separating the Ordovician period from the succeeding Silurian. 

Down the Des Plaines valley, about four miles below Joliet, and op- 
posite Flathead mound, are a few exposures of limestone near the old 
canal, which may be a part of the Cincinnati formation. The rock is 


GOI-DTHYVAITJ STRUCTURE OF BED ROCK. 




14 


THE DES PLAINES VALLEY. 


[BULL. NO. 11 


composed partly or argillaceous (clay-bearing) limestone, of dull greenish 
or bluish color (weathering buff), and partly of dense cherty beds. It 
is an exceptionally rich field for collecting fossils. Two of the siliceous 
layers are full of coiled gastropod shells (somewhat like No. 7, Plate 1) 
and cup corals (zaphrentis, No. 3, Plate 1). The latter are sometimes 
an inch long, and stand out from the weathered surface of the rock 
because they have been completely replaced by insoluble silica. In other 
beds of the limestone are to be found fragments of trilobites and brachi- 
opods and many pteropods (tentaculties) . This rock and its fossil con- 
tents are quite different from the Niagara limestone, as exposed about 
Chicago and Joliet; and it is probably a part of the Cincinnati form- 
ation. 

An abandoned quarry at the lower end of “Flathead” gives a good 
exposure of blue shales and shaly limestones typical of the Cincinnati 
formation. Certain layers here, notably two or three thin shaly la}^ers 
on the floor of the quarry, are full of fossils, especially strophomena 
(See No. 9, Plate 1), which are silicified, and show' plainly on the 
weathered surface. Traces of trilobites (See No. 5, Plate 1) are evident, 
but not sufficiently well preserved to make them of value for collection. 
In some of these a film of marcasite (iron sulphide) has replaced the 
original shell structure, and has since turned black, under exposure to 
the air. Orthoceras (a straight shelled cephalopod, (See No. 4, Plate 1) 
is also plentiful. No traces of crinoids, however, have been found. 
Other exposures of the Cincinnati formation are to be seen at the mouth 
of Pock run, and near Channahon. 

The Silurian Period . — With the changes which closed the Ordovician 
period, most of the interior of the continent became dry land, but as 
the Silurian period advanced, the epicontinental sea once more em- 
croached upon a part of the interior, perhaps creeping southward from 
Hudson bay (See Fig 4). It expanded over Illinois and Michigan, and 
southward and southwestward to Arkansas and Missouri, where it was 
presumably bordered by a land area. In this area a great limestone 
formation, the Niagara limestone, was laid down. This formation out- 
crops continuously for more than a thousand miles, from central New 
York to northeastern Iowa, and is widely exposed about the Great Lakes, 
forming the surface rock of the northeastern corner of Illinois. It takes 
its name from the falls of Niagara, for which the hard limestone is 
chiefly responsible. Since this is the only rock exposed in the Des 
Plaines valley, it deserves more than brief mention here. 

Where it has been penetrated by artesian wells in the vicinity of Chi- 
cago, the Niagara limestone has a thickness of from 250 to 400 feet. Its 
original thickness was probably still greater, for we cannot say how much 
was worn away from the top of it in the long interval of exposure and 
erosion between the Silurian and the glacial periods, when the rock 
surface was finally buried by glacial drift. Like most limestones, the 
Niagara limestones was originally an organic deposit — that it, an ac- 
cumulation of calcareous skeletons and shells of marine animals, worked 
over by the waves and currents, and ground to a fine calcareous mud. 




GOLDTH WAIT.] 


STRUCTURE OF BED ROCK. 


15 




Fig. 4. North America during (a) Niagara (later Silurian) and (b) later Devonian time. 


16 


THE DES PLAINES VALLEY. 


[BULL. NO. 11 


One of the distinctive features of the Niagara limestone is the wealth 
of fossils it contains. Evidently the interior sea was nearly free from 
river-borne sediment in many places. Hence it is believed the surround- 
ing lands ivere low, and the rivers sluggish. The water apparently was 
warm and of slight depth — perhaps not over 150 feet; for several species 
of corals grew in great profusion and built extensive reefs like those of 
tropical seas today. In eastern Wisconsin, especially, the reef build- 
ing habit was well developed, and there it appears that the coral reefs 
were tenanted by hosts of animals of other orders such as brachiopods 
and molluscs, all of which have contributed to the rack mass. Under 
the attack of the waves these reefs suffered continual grinding and recon- 
struction. The blocks and smaller fragments were piled up in embank- 
ments, while the sand and finely ground clay was spread out in broad 
sheets on the sea floor. Animal life, so profuse near the reefs, was more 
scantv on the broad smooth flats of white calcareous mud about them. 
These calcareous muds now constitute layers of compact, fine-grained 
gray limestone, nearly barren of fossils. 

Some idea of the variety of the marine animals of the Niagaran group 
ma} r be gathered from Plate 1, in which a few of the most characteristic 
types of fossils of the Des Plaines valley and Chicago district are to be 
seen. The resemblance between the fauna of northeastern Illinois and 
that of rocks about Hudson ba}^, Grinell land, north Greenland, and 
northern Europe, when contrasted with the markedly different fauna 
of the Appalachian district, warrants the belief that the interior sea 
extended northward from the Mississippi valley across Canada and 
north Greenland, and thence eastward and southeastward across Iceland 
to Scandinavia and England. In no other way can we satisfactorily 
explain the inter-migration of animals, whose habitat was the shallow 
shore zone. It is evident, too, that the climate in the northern hemis- 
phere at this time was much more equable than now, to enable the same 
corals to thrive in Arctic regions and in the lower Mississippi valley. 

The Niagara limestone, so far as known, is the bed rock beneath all 
but the extreme southwest portion of the Des Plaines valley. Not far 
below Joliet, as previously stated, the Cincinnati makes its appearance 
on the valley floor. Natural exposures of the Niagara occur on the bed 
of the Des Plaines near Lyons, on the floor and in the side bluffs near 
Lemont and from Lockport down to Joliet. On the tributary streams 
small exposures occur frequently near the main valley, where the side 
valleys have been cut most deeply, e. g., on Long run, Fraction run and 
Sugar creek. The limestone appears in the bed of Hickory creek at 
New Lenox, forming small rapids. A broad elevation of rock at Lyons, 
about which the Des Plaines river runs, between Eiverside and the Santa 
Fe bridge, is only thinly covered by drift. In many places here, the 
rock is within a foot or two of the surface, and is exposed in shallow pits 
and trenches in the fields. Stone walls built of the fragments, in a field 
east of Joliet avenue, contain an abundance of fossils, chiefly crinoids. 

A good field for collecting fossils of the Niagara limestone is the 
great pile of refuse along the side of the drainage canal near Lemont. 


STATE GEOLOGICAL SURVEY. 


BULL. NO. 11, PL. 1 



Fossils from the Niagara formation. Corals — Halycites (chain coral), (2) 
Favosites (honeycomb coral), (3) Zaphrentis (cup coral). Cephalopod — (4) Ortho- 
ceras. Trilobites — (5) Calymene, in foreground, two specimens; Dalmanites, in 
background. Brachiopods — (6) and (9). Gastropod — 7. Crinoid — Roots (8). 










































































































GOLDTHWAIT.] 


STRUCTURE OF BED ROCK. 


17 


The recently quarried blocks of rock, representing a vertical range of 
twenty-five feet where the canal has cut wholly in rock, frequently 
afford a wide variety of fossils. Trilobites ( Calymene Niagar&nsis 
No. 5, Plate I) may be collected, for instance, in the waste bank beside 
the canal just northeast of quarry No. 1, a mile and a half above Lemont. 

Perhaps the best known fossil in the Niagara is the orthoceras, a long, 
straight, cephalopod shell (No. 4, .Plate I.) While as a rule it is only 
one or two feet long, it attains sometimes a length of several feet. 
Naturally enough, it invariably lies with its long axis parallel to the 
bedding planes — a position which it would assume when it fell upon the 
sea floor. In this respect, it merely illustrates a rule that would apply 
to all fossils which have a marked flatness or length. They all tend to 
be deposited flat side down, or with their length in a horizontal position. 
Since the bedding planes are planes of easy separation when the rock is 
quarried, the surfaces of flagstones frequently show casts of the long 
chambered orthoceras shells. One can hardly walk three blocks in 
Joliet on a sidewalk of limestone slabs, without seeing at least one of 
these big shells. In the quarries about Joliet, crinoids, trilobites, brach- 
iopods, etc. may be collected, but usually with difficulty, since the massive 
gray beds which are so extensively used as building stone are as a rule 
barren. Fossils are more plentiful in the thin-bedded portions, which are 
not so often quarried. The abundance of nodules or lumps of chert, and 
of cherty layers in the limestone (recognized by its compact flinty tex- 
ture and splintery fracture, as well as by its superior hardness) is due 
in part, at least, to the burial of quantities of siliceous sponges on the 
ancient sea floor. Traces of the structure of these sponges have been 
found in the chert, under the microscope. 

The Devonian Period . — At the close of the Silurian period, the emer- 
gence of large portions of the interior of the continent greatly restricted 
the inland sea. Subsidences of the land and expansions of the epicon- 
tinental sea were renewed in the Devonian. By the middle of the De- 
vonian period (Hamilton epoch), the northeast part of Illinois (at 
least near Chicago) was again below the sea (See Fig. 4). The evidence 
of this is not found in broad exposures of Devonian rocks (like the belts 
of Niagara and Cincinnati) for the Devonian strata were stripped off 
by erosion long ago. All that remains to mark the former existence of 
Devonian sediments about Chicago are small pockets of clay, containing 
fish teeth and other fragments of Devonian species, in the cracks, here and 
there, in the Niagara limestone. The first discovery of this interesting 
feature was at a quarry near Elmhurst. Since then, similar Devonian 
exposures have been found in Fred Schultz's quarry, at Lyons. Stuart 
Wellers description of the Elmhurst locality is quoted below in some- 
what abbreviated form. 1 “At this locality the limestone is much frac- 
tured by two sets of gentle folds whose axes have a general northwest, 
southeast and northeast, southwest direction, joint cracks being well 
developed. Some of these cracks are several inches in width, and are 


l “A peculiar Devonian deposit in Northeastern Illinois Journ. Geol., vol. 7. 
pp. 4S3-4SS, 1899. 


18 


THE DES PLAINES VALLEY. 


[BULL. NO. 11 


in general filled with a black or bine clay. At one point, in the southeast 
face of the quarry, about eighteen feet below the glaciated surface of the 
rock, one of these joints is somewhat enlarged, to form a narrow tri- 
angular opening about six inches in width at the base and about sixteen 
inches in height. This opening, instead of being filled with clay, as are 
all the other larger joints in the quarry, is filled with a breccia composed 
of angular fragments of the adjacent limestone, imbedded in a dark 
brown arenaceous matrix. This matrix is abundantly f'ossiliferous, con- 
taining immense numbers of fish teeth and a smaller number of lingula 
shells and other bracliiopods, which indicate its Devonian age.'* The fish 
teeth represent a species ptyctodus calceolus and two new species of 
diplodus. Of these the teeth of ptyctodus are extremely abundant. The 
most plentiful brachiopod, lingula ligea , is known to occur in the De- 
vonian of New York and Nevada. One of the others, of which only one 
specimen was found, and the teeth of diplodus had previous been known 
only in carboniferous strata. Apparently, then, the deposit is of very 
late Devonian age. 


The nearest place where the Devonian is the surface rock is probably 
northwestern Indiana ; but there it is almost wholly concealed by glacial 
drift. “The nearest actual outcrop of Devonian is at Milwaukee, Wis- 
consin, eighty miles north of Elmhurst; and the nearest outcrop to the 
west is near Eock Island, Illinois, one hundred and thirty miles away. At 
both of these localities ptyctodus calceolus occurs, but the strata are 
believed to be somewhat older than the material from Elmhurst. 

“The presence of this Upper Devonian fauna at Elmhurst, buried as 
it is deep down in the Niagara limestone, indicates with certainty that 
during the greater part of Devonian time the region now known as 
northern Illinois was above sea level. It was part of what was probably 
a large land surface, stretching from the Wisconsin land on the north 
to the Ozark land of Missouri on the south. The waters which collected 
upon this land surface in part percolated through the underlying rock 
strata and by solution increased the size of many joint cracks. At a later 
period, near the close of the Devonian, when the sea again occupied the 
region, sand was sifted down into these open joints and with it the teeth ' 
of fishes which inhabited the sea thereabout. It is perhaps possible that 
the opening which has in recent time been uncovered at Elmhurst was 
during this late Devonian time large enough for the entrance of some of 
these fish, and that they sought this opening for shelter, much as fish at 
the present time enter similar openings. 

“The manner of communication between this opening and the surface 
is not clearly shown in the field, but arenaceous material with fragments 
of fish teeth is seen clinging to the quarry face to the left of and above 
the opening. This rock face is one side of a joint whose opposite 
side has been removed, through which there may have been communi- 
cation between the buried opening and the sea bottom above.” 

The similar exposure in the Lyons quarry was first observed and ex- 
amined about a year ago, by Messrs. C. E. Peet and Stuart Weller. The 


GOLDTH WAIT . ] 


STRUCTURE OF BED ROCK. 


19 


following brief description of it is written by Mr. Charles E. Decker, who 
visited the locality in May, 1907, after much of the rock had been 
quarried away : 

The fish teeth occur in a tension crack near the axis of a large fold in the 
south face of the quarry (described later). When examined a recent blast 
had torn away several feet of rock along the crevice, and some fragments of 
teeth were found in the debris among the loose rocks. The crevice is narrow, 
varying from one to two and a half inches in width, and extends downward 
about ten feet from the top of the quarry. It is filled with a dark, compact 
clay, in which there are many angular fragments of limestone. The fossil 
teeth are black. The largest one found is about three-sixteenths of an inch 
in cross section and three-fourths of an inch long. A small water-worn 
brachiopod was found in the same crevice, and near the edge of the crevice, 
a large fragment of a blunt tooth or tusk. 


The close of sedimentation . — At the close of the Devonian period, 
northern Illinois seems to have emerged again from the sea. Whether in 
succeeding periods it sank again to receive new sheets of sediments can- 
not well be determined, since later exposure to weathering and stream 
erosion has stripped off everything down to the Niagara limestone. It 
is possible that during the Mississippian and Pennsylvanian periods, 
when thick limestone and the coal measures were being deposited in 
the central and southern parts of the State, the sea covered the north- 
east corner of Illinois; but, if so, not a scrap of these rocks remains, so 
far as known, in the Des Plaines valley. Even the Devonian sediments 
were weathered and eroded except where tlie} r had penetrated deep 
cracks in the underlying limestone. By the close of the Paleozoic era 
at least, when the Appalachian ranges were elevated, and the whole 
eastern part of the continent emerged, the district in which the Des 
Plaines now lies became dry land. Its rock structure was thus prac- 
tically completed. The constructive process of deposition ceased, and 
the destructive process of denudation took its place. 


WARPING, JOINTING AND FAULTING OF TITE ROCKS. 

The uplifting of the rock foundation in a region is never accomplished 
without local warpings of the strata, extensive fracturing of a systematic 
sort, and more or less definite dislocation of the rock along certain frac- 
tures. So, in the quarries and other exposures in the Des Plaines valley 
the Niagara limestone exhibits signs of having been subjected to great 
strains, and of having yielded in a measure by the development of folds, 
joints and faults. 

Folds . — The elevation of the Silurian strata in this district — or, more 
accurately, the elevators, as there have doubtless been several move- 
ments — seem to have been pretty uniform in amount, for the bedding of 
the rocks as a rule remains nearly horizontal, or in about the attitude 
in which the sediments were laid down on the sea floor. In places, how- 
ever, the strata lie in an inclined position, with a dip of 10°, 20°, or 
30° from the horizontal. In the quarries near Cass and Grinton streets, 
on the east side of Joliet, dips of moderate amount can be measured. In 
Dellwood park, the rock shows a general dip 10° to 20° toward the south- 


20 


THE DES PLAINES VALLEY. 


[BULL. NO. 11 


west, but there are local undulations in the bedding. A good view of 
this can be had just below the upper dam on the north wall of the gorge. 
It is possible that some of the small folds or undulations are not deform- 
ations formed when the rock w r as uplifted after Devonian time, but that 
they are of earlier date. Folds of a puzzling nature and in part at least 
of Silurian age occur in the quarry of Fred Shultz at Lyons. 

The chief structural feature of the Lyons quarry is a gentle arch, or 
anticlinal fold, the axis of which runs north and south. Cross sections 
of it appear in the quarry walls on both the north and south sides. 
Superposed upon this major fold are domes and folds of minor im- 
portance, with axes running in various directions. They are best seen 
along the south side of the quarry, as the strata on the west side are 
approximately horizontal. The nature of these folds presents an inter- 
esting problem. It might indeed be questioned whether they are folds 
or constructional elevations formed at the time of deposition of the 
sediment which makes the limestone. In some cases the folds affect onlv 
a certain zone, the strata above and below being nearly horizontal. In 
one fold on the south side and still more notably on the west side, the 
beds thicken markedly towards the center of the fold. The fold itself 
is flanked by nearly horizontal layers, which thin out against the limbs 
of the fold and are overlain conformably by continuous horizontal beds. 
If corals were present in sufficient numbers, the arched structures might 
be taken for reefs. The strata underlying the arch seem to be crumpled, 
at the level of the quarry floor, as if there had been an actual deforma- 
tion. If so, it seems almost necessary to suppose that the folding oc- 
cured while the limestone was being deposited, because the arched beds 
are overlapped by horizontal beds without any intervening surface of 
erosion. If we can imagine earth movements to have folded the surface 
sediments without raising them above the sea, while deposition continued,, 
we satisfy both the peculiar overlapping and the thickening of the beds. 
Soft plastic muds or ooze might be squeezed or thickened by compression 
in the arches. 

Another puzzling relation of beds is seen at the southeast side of the 
Lyons quarry, where an anticlinal bend at the surface is directly over a 
synclinal bend, there being a lens-shaped mass between, with ill-defined 
bedding planes. 

A certain amount of warping is going on here at the present time 
where the rock floor of the quarry, under long exposure has expanded. 
One of these recent folds may be seen on the bottom of the quarry where 
two layers have been arched up so as to leave several inches of space 
between them. The same phenomenon has been observed in the quarry 
near Crvstal run, north of Joliet, and doubtless occurs elsewhere. 

Joints . — The same warpings which accompanied the elevation of the 
strata to their present positions involved tensions and strains which led 
to a wide-spread and systematic cracking and jointing of the rocks. 
These joints may be plainly seen in any quarry in the Niagara lime- 
stone. They are vertical cracks by which the rock mass is divided into 
rectangular blocks (Plate 2). The cracks are by no means Lap- 


GOLDTHWAIT.] 


STRUCTURE OF BED ROCK. 


21 


hazard, but run in sets or systems. Each set includes a large number of 
parallel or nearly parallel joints. Usually two sets are more conspicuous 
than the others, and these are perpendicular to each other. They run 
down to considerable depths, but just how far is unknown. In width 
they range from closed fractures to gaping fissures. The difference does 
not date back to their origin, but is due almost wholly to subsequent 
solution and weathering, accomplished by the penetration of air and 
water. Because of this enlargement of cracks, the jointing is much 
more conspicuous near the surface than near the bottom of the quarry. 
Joints appear to be much more numerous above than below. In a 
measure this is a real as well as an apparent truth. At the surface the 
tensions due to deformation are stronger than they are far below ground, 
and more cracks result. The photograph of the wall of Sugar creek 
gorge (Plate 2, B) shows a natural exposure of joint surfaces. 

Faults . — Signs of dislocation or faulting along joint fractures may 
be seen rarely in the Des Plaines valley. Where a set of stratified rocks 
is faulted, the relative motion on the two sides will be shown by the way 
the strata fail to match. Those on the (relatively) lifted side lie above 
those on the downthrown side. Such faultings have been very common 
in the past. They are known to have occurred in recent times and to 
be the chief cause of earthquake shocks. The recent earthquake of San 
Francisco 1 was -caused by a dislocation resulting in a horizontal shift of 
from eight to twenty feet, with but little vertical displacement. As a 
result the surface of the ground was broken, fences and car tracks offset, 
and in some places a low fault “scarp” formed. Even after erosion has 
obliterated the surficial indications of a fault, its existence can be told 
from the dislocated structure. Indeed, in most cases faults are discovered 
in this way, for as compared with the rapidly changing form of the sur- 
face, underground structure is permanent. In the district about the 
Des Plaines valley faults are relatively rare and of small measure. 
Occasionally on the wall of a quarry one may see a joint crack at which 

there is a break in the continuity of strata. This seldom amounts to 

# 

more than a few inches. 

The fault best shown in this district is near Joliet. It crosses a little 
gorge out by Sugar run between the Alton railway and the slaughter 
house road. The walls of this gorge are vertical joint faces, developed 
by the tearing off of blocks. As usual, two joint systems, nearly at right 
angles, are dominant. On the map of this district (Plate G) the joint 
systems are indicated bv two crosses. It is worthy of notice here 
that where the limestone contains hard nodules of chert or flint the 
joint cracks cut through them like a knife, rather than pass around them 
irregularly. Obviously, the cracks occurred after the rock became thor- 
oughly compact and hard. Scarcely one hundred feet above the bridge 
at the slaughter house road, the fault shows in cross section on the south- 
east wall of the gorge (Plate 2, B.) Three cherty bands in the lime- 
stone mark out the stratification, and serve to distinguish the offset on 
the right and left side of the fault plane, which is one of the master 


l Sec Salisbury, “Physiography,” pp. 419-426. 1907. 


22 


THE DES PLAINES VALLEY. 


[BULL. NO. 11 


joints running northwest-southeast. The block on the right (southwest) 
side has risen fully a foot with reference to that on the left. On the 
northwest side of the gorge the continuation of this fault is somewhat 
concealed, but careful search will discover the extension of the same joint 
plane, which is here accompanied by a zone of crushed or “brecciated” 
rock between the dislocated sides. The rock, though decayed, has not 
wholly lost the half polished, half shredded surface produced by the 
slipping, a surface known to miners and geologists as “slickensides.” 
It is not sufficiently well preserved, however, to show the exact direction 
of the dislocation. 


STATE GEOLOGICAL SURVEY, 


BULL. NO 


PL. 2 


. 11 


* 



A. Lock on the IUinois-Michigan Canal, above Joliet. 



B. Fault in the Wall of Sugar Creek Gorge. The fault fracture cuts the 
large rectangular opening. The block on the right is a foot above that on the left. 





































- 













































































































































GOLDTHWAIT.J 


23 


CHAPTER III. 


THE CONCEALED SURFACE OF THE BED ROCK. 

SIGNIFICANCE OF THE; BURIED TOPOGRAPHY. 

Except in a few places, as in the bluffs which overlook the Des Plaines 
valley at Lemont, Lockport and Joliet, and where quarries have been 
opened, the bed rock of this region is concealed beneath a sheet of 
glacial drift or of recent alluvial material. So few are the exposures 
of rock and so limited in extent, that it is difficult from them to form 
a distinct picture of the buried bed rock topography. Some information 
can be gained from records of wells where the thickness of the drift 
cover has been measured, yet these data are very limited, and show little 
more than the fact that the bed rock surface is uneven, having a relief 
of 75 or 100 feet in short distances. The surface of the rock, it ap- 
pears, is much more irregular than the old lake plain, and fully as un- 
even as the Valparaiso moraine ; yet the bed rock topography bears no 
relation whatever to the topography of the overlying drift. We can 
form no correct idea of the concealed rock surface from the location and 
extent of the moraine ridges or the lake plain. 

It is of deep significance that we have in this region the Niagara 
limestone of Silurian age overlain immediately by glacial drift. Evi- 
dence has already been presented, in the remnants of Devonian sediments 
preserved in deep cracks of the underlying limestone, that a considerable 
period of time elapsed after the Silurian period, during which a shale 
formation was deposited on the sea floor, and subsequently, after emer- 
gence, was stripped off by erosion. It remains for us now to extend this 
conception of the long interval of erosion which succeeded the Devonian 
period and antedated the deposition of the glacial drift, by realizing that 
the Devonian formation belongs far back in geologic time while the 
glacial drift is of very recent date. The time interval registered by the 
sharply defined surface which separates the eroded bed rock from the 
unconsolidated drift is enormously long. This is shown conclusively by 
the occurrence elsewhere of a great series of formations younger than 
the Devonian and older than the glacial drift. These formations are 
absent from northern Illinois, either because this region stood above the 
sea and so received no sediments, or because if once deposited they were 


24 


THE DES PLAINES VALLEY. 


[BULL. NO. 11 


subsequently removed by erosion. In either case, the time required for 
the deposition of the formations which elsewhere lie between the De- 
vonian and- the drift was immeasurably long. 

With this brief mention of the importance of the bed rock surface 
as a record of a great interval of erosion we may turn to the history of it. 

The bed rock topography has been moulded by two agencies; (a) by 
running water and the various processes of weathering, and (b) by the 
great ice sheet, which, by erosion and by the deposition of drift, modified 
to a considerable extent the form of the surface. 

PRE-GLACIAL DENUDATION. 

Deductions from the “ Driftless Area ." — The pre-glacial condition of 
the topography can be judged best by the topography of the driftless 
area of northwestern Illinois and southwestern Wisconsin. The rock 
structure of that district and the history through which it has passed 
are comparable to the district surrounding the Des Plaines valley, but the 
driftless area, unlike the surrounding region, was never covered by the 
ice sheet, so that its pre-glacial surface is preserved, though modified 
to some extent by the erosion of later time. 

With the emergence of northern Illinois from the interior sea, prob- 
ably at the close of the Devonian, the rocks which had been deposited 
were exposed to agencies of decay and of valley excavation. In the 
long periods of time which followed, while the Coal Measures of Illinois 
and other states were accumulating ; while the Alleghany mountains 
were folded, worn down to a plain, and again uplifted and deeply dis- 
sected by erosion : and while the broad Coastal Plain of the Atlantic sea- 
board and the gulf were being built; during all this time, the surface 
of the rock structure of northern Illinois was being lowered by erosion. 
Once at least it was worn down to an almost featureless plain, a “pene- 
plain,” a condition reached only when the land stands still for an almost 
inconceivably long period of time, and river systems are enabled to com- 
plete their work of reducing the entire systems of their basins to a low- 
land near sea level. At length this base leveled plain was lifted up by a 
broad warping movement, while the revived rivers sank their channels 
below the rising plain and a new set of valleys was worked out. Grad- 
ually these valley systems were extended as well as deepened, until today 
the region is an upland of rolling prairie, a great sea of hills and valleys 
with smooth flowing outlines. The hill tops rise to nearly the same 
level, and the main divides or ridges between the valley systems are 
remarkably flat topped, representing the remnants of a once continuous 
peneplaip. Here and there a higher knob or “mound” rises the upland 
level, a residual hill which escaped base-leveling. But, for the most 
part, the relief is one of monotonous regularity. Long continued decay 
of the rocks has produced a residual soil several feet thick, which passes 
downwards by unbroken transition into the firm unweathered rock. 

The pre-glacial topography . — A surface similar to that of the drift- 
less area was developed before the glacial period in northeastern Illinois. 
At the same time, it is altogether probable that a broad lowland had 


■GOLPTHWA IT.] 


SURFACE OF BED ROCK. 


25 


been developed where Lake Michigan now lies, for the rock formations 
which underlie the lake are a series of soft Devonian shales and sand- 
stones which would be reduced much faster than the hard Niagara 
limestones farther west. Possibly also, there was a somewhat distinct 
escarpment running from north to south in the western part of our dis- 
trict, owing to the greater reduction of the Cincinnati shales, which lie 
west of the Niagara limestones. The hills carved out of the hard lime- 
stones at Joliet may have descended rather abruptly a few miles west of 
the city to a lower, flatter district occupied by the shales. 

The development of underground drainage . — The limestone of this 
region not only suffered decay and erosion at the surface, but was at- 
tacked by ground water. Any rock structure so extensively affected 
by joints permits water to work its way downward at a rather rapid rate. 
This water, charged with a small amount of certain acids, the carbon 
dioxide -from the air, the humus acids from the soil, can slowly dissolve 
certain rock constituents, especially limestone, which is very largely 
composed of soluble lime carbonate. Thus it comes about that material 
is dissolved from the two faces of every joint crack in limestone, and the 
joint is slowly enlarged. Under favorable conditions definite under- 
ground stream channels mav be eaten out in time. These may grow 

O %j 1/ o 

into large passages and caverns. It is in fact in just this way that the 
great limestone caverns of Indiana, Kentucky and Virginia were made. 
If a cavern is not far underground and is so greatly enlarged that the 
roof falls in, a “sink” or “sink hole'" results. These sink holes are saucer 
shaped depressions in the ground. While in some cases they originate 
after the fashion just described, it is probable that most sink holes are 
developed by local enlargement of innumerable small passageways 
through which water drains downward from the surface, and without 
the development of any great cavern immediately beneath. Surface 
drainage flowing into sinks increases their size, and eventually almost 
the whole drainage of a district may enter sinks and follow underground 
channels. This condition has been reached in the interior of Florida. 

While no such wholesale development of sinks and subterranean 
streams occurred in northern Illinois before the ice age, sinks are known 
to exist there, in spite of the fact that the drift so generally conceals 
them. Two or three good sized hollows, leading to caves of unknown 
extent, could formerly be seen in the west part of Joliet, near Jasper 
street and Kaynor boulevard. They have been more or less filled up with 
rubbish in recent years, so that they cannot satisfactorily be examined. 
In places, small tunnels or openings in the limestone may be seen in the 
quarries about Joliet, though none of them are of striking proportions. 
One appears in the northeast corner of the quarry near Grinton and 
Jackson streets. It is a thin horizontal opening worked out along a 
bedding plane in the limestone, close to the present quarry floor. The 
steady flow of water through these openings renders them most unwel- 
come to the quarrymen, necessitating the constant use of pumps. It is 


26 


THE DES PLAINES VALLEY. 


[BULL . NO. 11 


said that a spring issuing from the limestone near here, was formerly 
a regular stopping place for the stage, as it passed down the Des Plaines 
valley through Joliet. 

GLACIATION. 

The Glacial Period . — The rolling upland with its maturely developed 
valley systems and its residual soil was destined not to remain. An 
extraordinary change of climate led to the development of a great ice 
field over much of the northern part of North America. The extent of 



Fig. 5. Map of area covered by the North American ice sheet of the glacial 
epoch at its maximum extension, showing the approximate southern limit of glaci- 
ation, the three main centers of ice accumulation, and the driftless area within the 
border of the glaciated region. ( Courtesy of U. S. Geological Survey.) 

the ice sheet (shown in Fig. 5) was some 4,000,000 square miles, fully 
the size of the ice sheet which now covers the Antartic continent. Why 
such an enormous ice sheet grew up in North America, with its centers 
of accumulation nearly thirty-five degrees away from the pole, has 
never been satisfactorily explained. It has been ascribed, in turn, to 


GOLDTHWAIT.] 


SURFACE OF BED ROCK. 


27 


a general uplifting of the continent to an altitude above the snow line; 
to a shifting of ocean currents by up-warpings of the sea floor ; to certain 
changes in the earth's planetary relations (eccentricity of the orbit and 
precession of the equinoxes) which might rarely combine to give a series 
of ice caps, alternately at the north and south pole ; to a shifting of the 
poles themselves, with respect to the crust or outer shell of the earth ; 
and to changes in constitution of the atmosphere, wherein slight en- 
richment in carbon dioxide gas, accomplished by certain geologic and 
geographic changes, might bring about a cool moist climate. All these 
except the last have met serious objection, and while this cannot be 
said to have been demonstrated it seems the most satisfactory yet sug- 
gested. 

The North American ice sheet, as the map (Fig. 5) indicates, probably 
extended as far north as the continent itself. Greenland is believed to 
have been covered by its own separate ice cap. A similar ice sheet, with 
its center on the Scandinavian peninsula, covered all of northwestern 
Europe and most of the British Isles. On the Alps there was a smaller, 
isolated ice field, from which great tongues of ice moved down the main 
valleys. 

It must not be thought, however, that the North American ice sheet 
was a group of narrow glaciers moving out from an elevated mountainous 
center. While the Canadian highlands, from which it spread, stand 
somewhat above the general level of the upper Mississippi valley, the 
motion of the ice was not controlled by the topography. Rather was 
it a vast sheet, radiating out from three (possibly four) centers, with the 
ice from at least two of them coalescing to form a single great ice cap. 
The ice in the western mountains appears to have remained measurably 
distinct. 

The history of the glacial period was complex. It was made up 
of several glacial and interglacial epochs. In the former the ice sheets 
grew larger ; in the latter they dwindled, or disappeared altogether. The 
glacial epochs evidently represent periods of severer climate, while the 
interglacial epochs mark times of milder climate. The glacial period 
was therefore a period of climatic changes. We seem now to be living 
in a post-glacial epoch, but if another glacial epoch should follow, the 
present would prove to have been an interglacial epoch. It may be said, 
in this connection, that some of the interglacial epochs seem to have been 
much longer than the time since the ice last withdrew. 

The ice sheet was thick enough to cover the hill tops everywhere with- 
in reach, and even to bury the mountains of northern New York and of 
New England. We may get some idea of its thickness over the Des 
Plaines basin by measuring the distances out to the border of the 
glaciated area and assuming a surface slope in this distance, equal to 
that of the Greenland ice cap. When the ice had its greatest extent in 
Illinois (in the “Ulinoian” epoch) its outer edge was more than 300 
miles south of the Des Plaines district (see Fig. 6). If the average 
slope of its surface at that time was thirty feet per mile, i. e., about the 
same as that of the interior of the Greenland glacier, the thickness A 


28 


THE DES PLAINES VALLEY. 


[BULL. NO. 11 


ice over the Des Plaines basin was some 9,000 feet. It seems unlikely, 
however, that such a steep slope as that would continue so far from the 
ice margin. Nansen, in his trip across Greenland, found that on the west 
side (where the slope was gentler than on the east) the surface of the 
ice cap rose to 6,600 feet in the first seventy-six miles, and after that at 



GOLDTH WAIT. J 


SURFACE OF BED ROCK. 


29 


an average rate (constantly decreasing) of twenty-six feet per mile. 
If we assume the same rate for Illinois, we get 6,600 feet for the first 
seventy-six miles back from the ice border, and 5,850 feet for the 225 
miles following, or a total thickness over Joliet and Chicago of over 
12,000 feet. There is reason to believe, however, that the Greenland 
ice sheet covers a high mountainous region from which there is a rather 
steep descent to the sea; and that the slope of the surface of the ice 
sheet is steeper on that account than it would be over a flat region like 
Illinois. So far as this is true it should lead us to reduce the estimate 
of thickness accordingly. We may reasonably believe, however, that 
during the Illinoian ice invasion the ice sheet was several thousand 
feet thick over northeastern Illinois. During the last glacial epoch, how- 
ever, the ice advanced only a short distance southwest of the Des Plaines 
valley, and its thickness over that area was probably not more than a very 
few thousand feet. 

For a long period, probably a hundred thousand years, this great cap 
of ice was a powerful agency in modifying and reshaping the surface 
features of this district. When it finally melted away, on the establish- 


(a) (b) 



Fig. 7. Section showing (a) residual soil, passing downward into rock, and 
(b) glacial drift overlying a glaciated rock surface unconformably. 

ment of the present climate, a wholly new topography appeared. In 
two distinct ways the ice sheet had changed the topography of the sur- 
face. It had carried away the residual soils and most of the loose rock 
within the zone of surface decay and disintegration, and as a rule it 
ground, scraped, and scoured the firm rock below until its surface was 
reduced, in many places at least, several feet below its former position 
(See Fig. 7). 

The smoothing and striating of the roclc surface . — The appearance of 
a strongly glaciated surface of rock is so characteristic that it deserves 
more than mention. The drift-shod ice, moving slowly along over the 
rock floor and pressing down upon it with tremendous weight, rasps 


30 


THE DES PLAINES VALLEY. 


[BULL. NO. 11 


and scours it. The finely comminuted clay or “rock flour” which makes 
up a large part of the drift, probably lubricated with water, smooths 
and even polishes the rock surface. Coarser particles in the ice such as 
sharp cornered bits of rock, are held firmly against the bed rock like en- 
graving tools, scratching the surface more or less deeply in the direction 
of glacier motion, until the cutting edge is blunted or the pebble turns 
around. These scratches or “striae,” where best formed (on rock of fine 
grain, dense texture, but of relatively slight hardness, like certain layers 
of the Niagara limestone) begin abruptly and gradually narrow or tail 
out in the direction in which the glacier advanced. They vary in size 
from scratches of a hair’s breadth to grooves several inches in cross sec- 
tion. Large bowlders were probably the carving tools in the case of 
the larger grooves. In length the fine scratches are to be measured by 
inches rather than feet. With a little practice, striae can be distinguished 
readily from cracks. The scratches are mere surface markings, and 
can be seen only on well smoothed surfaces of freshly exposed rock. 
Cracks, of course penetrate the rock and may occur on any surface. As 
a rule the scratches at a given point follow a single direction, which is 
that of ice motion when the rock surface was last covered by ice. Oc- 
casionally, however, two or more sets of scratches cross one another, testi- 
fying to the local shifting of the direction of ice movement. 

Striated rock surfaces are to be looked for where the drift has been 
only recently stripped away, as around the borders of freshly worked 
quarries. Where a rock surface has been exposed even for a few years 
the decay of the limestone has usually obliterated them. Moreover no 
striae are likely to remain where the rock surface was washed by streams 
during the retirement of the ice sheet, and was buried by gravels. For 
these reasons chiefly, striated surfaces are rarely seen near Joliet. The 
rock floor of the valley was cut down by an ancient river (the outlet 
of extinct Lake Chicago) and the rock up to the height of some fifty 
feet on either side of the valley was washed by gravel-bearing streams. 
A smoothed rock surface has been recently exposed beside the track of 
the Coal City branch of the Chicago & Alton railway, just southeast of 
the switch house on South Chicago street. No scratches can be seen on 
it, however, and the gravelly and boulderv drift which has been stripped 
away seems to indicate that the surface, if ever scratched by the ice, was 
subsequently eroded by running water. 

The burial of the rock surface with drift . — Over the glaciated surface 
of the bed rock, the glacier spread a sheet of rock debris or “drift,” 
which it had collected on its way southward, and which it was unable 
to carry farther out to the position of its extreme border in southern 
Illinois. So the residual soils of pre-glacial time were taken off, the 
underlying rock worn down to some extent, and then buried by a sheet 
of drift of variable thickness. The contact of the rock and the drift is 
therefore a true “unconformity,” the record of an interval of erosion 
between two widely separated periods of deposition. Too much emphasis 
can not be placed on this feature, so characteristic of the glaciated region. 


GOLDTH WAIT . ] 


SURFACE OF BED ROCK. 


31 


The buried topography . — The rolling upland of pre-glacial time was 
probably modified only slightly by glacial erosion. There is no evidence 
that any profound erosion took place. The pre-glacial valleys were 
probably somewhat deepened and widened, and the hill tops were some- 
what reduced, but the undulatory character of the bed rock surface re- 
mained, with probably little change in the amount of unevenness. This 
fact is suggested by data from wells and by the exposures in quarries, 
and alono- the vallevs where the drift has been removed. Take, for ex- 
ample, the profile of rock along the Des Plaines valley from Lemont to 
Willow Springs. At Lemont the Niagara limestone appears on either 
side of the valley in the bluffs, to a height of about fifty feet above the 
valley floor, or sixty feet above Lake Michigan. As exposed in the wall . 
of the quarry west of the village the surface of the rock declines grad- 
ually to the level of the valley floor in two miles. East of Lemont, like- 
wise, the surface of the bed rock descends, reaching the level of the river 
within a mile and a half. Opposite the mouth of the "Sag” the bed 
rock (by measurements along the drainage canal) ranges from fifteen 
to thirty-five feet below the valley floor, or five to twenty-five feet below 
Lake Michigan, indicating a change of altitude of the rock surface of 
eighty-five feet between the highest point, at Lemont, and the lowest, 
near Sag bridge. That the bed rock surface rises and falls as much as 
eighty-five feet, even, in comparatively short distances is indicated by 
the presence of a rock outcrop on Saw Mill creek, about a mile north- 
west of Sag bridge, and at a height of nearly seventy-five feet above 
Lake Michigan. This means for that vicinity at least a vertical range 
of 100 feet in a mile. It is not likely that these measurements (the 
highest and the lowest) are extreme; rather does it appear that the 
rock surface rises and falls with moderate slopes in innumerable hills 
and valleys of about the size and height of the morainic hills on Mt. 
Forest island. 

In places the surface of the bed rock after glaciation had really pre- 
cipitous slopes. Such was the case, apparently, noar Lemont, where sharp 
rock bluffs overlook the valley floor. At first sight these bluffs might be 
thought to be the work of the Des Plaines river or its ancestor, the outlet 
of glacial Lake Chicago, which once poured through the valley, and which 
might easily have cut a deep notch through the bed rock had there been 
a rock barrier athwart its course at Lemont, Such an explanation for 
the bluffs and the rocky floor of the valley has in fact been entertained. 

The contrary belief, i. e., that the valley, with its rocky floor and sides, 
was already in existence when the ice sheet last covered the district, and 
that no rock barrier crossed the Chicago outlet at Lemont, is based on 
the distinctly glaciated character of the bed-rock floor of the valley at 
several points between the opposed bluffs. At the quarries on the north 
side of the valley about Lemont, near where the Santa Fe railway turns 
obliquely across the river and the drainage canal, the bed rock floor of 
the valley at the base of the bluffs is smoothed and polished and distinctly 
scratched. The striae run about south 50° west, parallel to the axis 
of the valley. The best exposure noted is at the northeast end of the 
quarries, where a thin covering of glacial drift in April, 1907, had just 


32 


THE DES PLAINES VALLEY. 


[BULL. NO. 11 


been stripped from- the rock floor. Clearly this spot in the valley, at 
least, was once scoured by the glacier. Similar exposures a few hundred 
yards away confirm this view, and suggest that the whole valley was 
once filled and buried by glacier ice. Such glacial markings on the 
valley floor have been noted before at Lemont. A strongly glaciated 
surface, exposed in the bed of the Chicago drainage canal at this place, 
was described and pictured by Leverett in his monograph on “The Illi- 
nois Glacial Lobe ." 1 It is, of course, not safe to insist that no rock bar- 
rier could have crossed the valley somewhere just above or below Lemont, 
until it is known that the floor of the valley shows marks of glaciation 
as far down-stream as it is bordered by rock bluffs — a matter as yet 
undetermined. But the evidence just reviewed strongly favors that view. 
The valley at Lemont seems to be a glaciated valley, and not a post-glacial 
valley of river excavation. Besides throwing light on this question of 
a rock barrier at Lemont, the striated surfaces at the base of the bluffs 
illustrate the local steepness of bed,-roc*k slopes which were covered and 
scrubbed by the ice. 


M_J. S. Geol. Surv., Monograph 38, p. 416. 


goldth wait . ] GLACIAL AND INTER-GLACIAL DEPOSITS. 



CHAPTER IV. 


THE GLACIAL AND INTER-GLACIAL DEPOSITS. 

The nature and history of the extinct North American ice sheet has 
been outlined in the preceding chapter. The manner in which it eroded 
the surface of the underlying rock has also been briefly told. We have 
now to consider in some detail the deposits which the ice left on its 
retreat, and those laid down in inter-glacial periods. To the deposits of 
glacial drift we owe all the main features of the present topography and 
indeed most of the details of the surface. 

DISTRIBUTION" AND SURFACE FORM OF THE DRIFT. 

The map of the Des Plaines district (Plate 1) and an introductory 
sketch of the leading features of relief on pages 3 and 4 indicate the 
massing of the drift into parallel belts of upland, known as terminal 
moraines. Each of these moraines marks a stage in the recession of the 
ice border, when the rate of melting was temporarily checked and the 
edge of the ice became nearly stationary. At such times the drift which 
was being moved forward to the melting border and deposited there, 
accumulated to great thickness. When the ice border receded a relatively 
smooth lowland was laid bare behind the belt of thick drift. This ex- 
tended to the time when another halt of the ice caused the making of 
another ridge of drift. 

It is characteristic of these terminal moraines to have a very uneven 
surface. The unevennesses consist of depressions and swells, more or less 
like upright and inverted saucers, yet too irregular in outline to be de- 
scribed accurately in those terms. The range of undulation and the 
angle of slope vary in the different moraines. They are greatest on the 
largest one, the Valparaiso moraine, reaching on Mt. Forest Island a 
relief of over fiftv feet between hill top and vallev bottom. At Hinsdale 
the relief is somewhat less marked, with a range of about thirty feet, 
and around Elmhurst the eastern portion of the moraine has very wide 
flattish sags and swells. On the smaller moraines, the Minooka till ridge, 
the west ridge of the Valparaiso morainic system north of Joliet, and the 
lake border moraines, the undulations of the surface are very faint com- 
prising long gentle slopes which rise and fall no more than fifteen to 
twenty feet in long, distances. The size of^ the hills is also variable. 


M 


THE DES PLAINES VALLEY. 


[BULL. NO. 11 


They are commonly half a mile to a mile in longest diameter. The 
hollows are often enclosed basins, in which surface water collects to form 
swamps or little ponds in wet weather. This is favored by the im- 
permeability of the compact clay of which moraines are largely composed. 
There seems to be little regularity in the trend of swells and sags, for in 
some places the} r appear to run roughly parallel to the former border of 
the ice and in other places they are prevailingly perpendicular to it. 

The cause of the marked irregularity of the surface of moraines is 
to be found in the variability of conditions under which the moraines 
grew up. In the first place, the drift was not evenly scattered through 
the ice, so that much more reached the melting border of the ice at some 
points than at others. Low mounds and hollows on the surface of the e 
deposit naturally resulted. Secondly, the ice edge was oscillating back- 
ward and forward locally at different rates, so that the drift was spread 
out more in some places than in others, and deposits once made were 
frequently overridden bv local re-advances of the ice. In some cases, 
moreover, blocks of ice were left behind as the ice retreated. If these 
were surrounded or buried with gravel their melting may have led to 
the formation of hollows in the surface of the drift. 

The deposit left beneath the ice, between the morainic ridges, is 
known as the “ground moraine." This too has its swells and hollows, 
but in this region they are much less pronounced than those of the 
terminal moraines. The belts of ground moraine have the appearance of 
rather smooth plains. The broad shallow valley followed by the upper 
Des Plaines river, above Riverside, is one of these plains. Its lower 
portion, as well as the adjoining Chicago plain, was afterwards covered 
by the glacial Lake Chicago, and the initial smoothness was increased 
bv the leveling action of waves and currents, which tended to cut down 
the elevations and to build up the depressions. The lake plain in many 
places appears to be absolutely flat for miles. -This is its appearance 
at the city limits of Chicago, near Archer avenue, and west of Harlem, 
around “Broad view A 

THICKNESS OE THE DRIFT. 

The undulating surface of the bed rock, and the equally irregular 
surface of the drift, with no correspondence in position between the two, 
combine to give the drift a very irregular thickness. Locallv, as already 
remarked, the drift is almost or quite absent. There are other places 
where well borings show it to be more than 200 feet thick. As a rule, 
however, in the neighborhood of the Valparaiso moraine, where we may 
expect the maximum thickness • for the Des Plaines valley district, it is 
100 to 150 feet thick. At five localities in our district well records col- 
lected by Leverett 1 show thicknesses as follows : 

Arlington Heights (about 150 feet below crest of moraine) 128 

North of Arlington Heights (20 to 30 feet above station) 190 

Elmhurst .- 98 

Crest of moraine northwest of Lemont 150 

Crest of moraine east of Lockport 1 115+ 


1 “The Illinois Glacial Lobe.” U. S. Geol. Surv., Monograph 38, p. 354. 1899. 


goldth wait . J GLACIAL AND INTER-GLACIAL DEPOSITS. 


This gives an average of 136 feet along the axis of the moraine. The 
greatest thickness in the table is by no means a maximum, but it is not 
likely that the drift is much over 250 feet thick anywhere in the Des 
Plaines basin, since out of 68 well records cited by Leverett on the Val- 
paraiso moraine between northern Illinois and southwestern Michigan, 
only four are certainly over 250 feet, and only one is over 300 feet. The 
deepest visible section through the drift in our district is two or three 
miles west of Lemont, where the broad valley crosses the axis of the 
great Valparaiso moraine, and the extensive stripping of the rock in the 
bluff on the south side of the valley has freshly exposed the drift to a 
depth of some 75 feet. 

COMPLEXITY OF THE DRIFT. 

Because of the complexity of the ice age, the series of advances and 
retreats of the ice, the drift does not consist merely of a single sheet, 
but of several overlapping sheets, deposited by the successive glaciers. 
It is through the study of these several drift sheets that investigators 
of glacial geology, during the past twenty-five years have worked out 
the fact of successive glaciations. In Illinois and the adjoining states, 
the later ice advances as a rule fell short of the earlier, so that each of 
the five drift sheets is to be found locally as a surface deposit south 
of the outer border of the next younger sheet. Even where an earlier 
sheet was run over by a later advance of the ice, the old drift, buried 
beneath the later drift sheet, may sometimes be found where streams have 
excavated valleys through the deposits, or some other section, natural or 
artificial, has been made. An older drift sheet is often separated from 
a younger one above either by an old surface with its evidences of erosion, 
soil decay, and vegetation (in the form of peat beds, tree trunks, etc.), 
or by stratified deposits of sand and gravel which indicate deposition 
by rivers or lakes during the inter-glacial epoch. Often, however, the 
older drift sheet was wholly destroyed before the deposition of the newer 
drift, either by surface erosion or by the later ice advance. Conse- 
quently one rarely finds in any single exposure more than two or three 
glacial and inter-glacial deposits, and in most cases there is only the last 
drift ' sheet over the bed rock. The five drift sheets recognized in the 
upper Mississippi valley as marking five distinct advances of the ice have 
been named in the order of their age (1) sub-Aftonian, or Jerseyan, 
(2) Ivansan, (3) Illinoian, (I) Iowan, (5) Wisconsin. The last has in 
turn been subdivided into the early and the late Wisconsin stages. 

THE TWO KINDS OF DRIFT. 

The fragmental rock material which was transported by the ice sheet 
and sooner or later deposited in a new locality is known as the “drift A 
The greater part of it was deposited directly by the ice. This is known 
as “till." But much of the drift was worked over by running water as 
the ice sheet melted awav, and was laid down in beds or strata. This is 
known as “stratified drift." It resembles till in one respect, in being 


36 


THE DES PLAINES VALLEY. 


[BULL. NO. 1J 


composed of fragments of rocks of very many different sorts; but it 
differs from till very markedly in physical structure, possessing stratifi- 
cation, which is unknown in ice-laid drift. The distinction is a funda- 
mental one, and will be emphasized in the following discussion of the 
till and of the stratified drift. 

The ice-laid drift or “till ”. — The most striking character of the till 
is the great range in size of the fragments which compose it, and the 
entire absence of separation of coarse from fine. Large bowlders, cob- 
bles, pebbles, sand, clay, and the finest “rock flour” are mingled in ab- 
solute confusion. This arises from the fact that a glacier has great power 
as a transporting agency ; the heaviest bowlder can be carried on its sur- 
face or within its frozen mass almost as easily as a particle of clay. 
Where the strength of the ice movement is locally diminished, deposi- 
tion affects coarse and fine alike. There results a heterogeneous mixture 
known sometimes as “bowlder clay” (synonymous with “till”.) Not so 
with deposits which are laid down by running water or by wind. These 
two agencies are very limited in their carrying power. Each variation 
in the strength of a current of water means a variation in the size of 
the particles which it may carry or deposit. Accordingly, at one time 
fine sand may be deposited, and later, if the current becomes stronger, 
coarse sand or gravel may be deposited at the same place. With wind a 
similar change leads to successive layers or beds in the deposit, although 
wind is of course not strong enough to transport gravel. Ice-laid de- 
posits, then, are peculiar in their absence of stratification. 

Another criterion of ice deposits is the shape of the stony ingredient. 
Although many of the bits of rock in bowlder clay are rounded like river 
or beach pebbles (and it is significant in this connection that the diabase 
and granite pebbles and bowlders which have come far are usually 
rounder than the limestone fragments of local derivation) a large num- 
ber are angular or sub-angular, with snubbed ends, rounded edges, and 
smoothed and striated sides. (See Plate 3, No. 2). The striae resemble 
those of a glaciated bed rock surface, and are made in just the same way, 
only the stones of the drift are in motion, and scratch against one another 
as well as against the bed rock. If a stone in the till is decidedly longer 
in one direction than in others, its striae as a rule run parallel to its 
length, because the stone tends to orient itself in the position in which it 
- will offer least resistance to the abrading force. This feature is illus- 
trated in the glacial stone in Plate 3. 

As regards the composition of its rock particles, the till exhibits a 
very remarkable variety. The pebbles and bowlders show a lithological 
heterogeneity far greater than any lot of pebbles that a river or a lake 
alone would be likely to collect. While most of the pebbles resemble the 
underlying rock, many of them correspond to rock formations which 
occur not nearer than 50, 100, or even several hundred miles. Such, for 
instance, are the granites, diabases, quartz-porphyries and amygdaloids, 
which came from northern Wisconsin or beyond, and the quartzites which 
came from the same region or perhaps from certain small areas of 
quartzite in south central Wisconsin. No agency except ice is known, 
by which rock material would be collected from such widely separated 


STATE GEOLOGICAL SURVEY. 


BULL. NO. 11, PL. 3. 



Pebbles from the drift. (1) glacial gravel, (2) till, (3) 

cemented by carbonate of lime. 


gravel pebbles partly 






' ' ; 
























































GOLDTHWAIT.] GLACIAL AND INTER-GLACIAL DEPOSITS 


37 


sources and transported to a single place hundreds of miles away. Espec- 
ially is this true when we remember that coarse and fine are intimately 
commingled, and that the material came from various river basins. 

LIST OF ROCKS FOUND IN THE TILL. 

A list of several kinds of rock, represented by pebbles, bowlders and 
other fragments in the drift, together with simple means of identifying 
them, is given below : 

Igneous Rocks. 

(Rocks solidified by cooling from a hot, molten condition.) 

Granite. — Crystalline, usually coarse-grained, speckled appearance due to 
presence of many separate crystals of three or more kinds of minerals, chief 
among which are: Quartz (white or sugary, and very hard); Feldspar 

(whitish or reddish, according to impurities and decayed condition, in part 
with somewhat rectangular outline, and “cleavage” surfaces which reflect 
the light, hard); Hornblende (black, or greenish black if decayed, often in 
small irregular bunches); Mica (white or black, cleaves in thin flakes which 
reflect the light brilliantly, soft enough to be cut easily with the knife). 
Granite is sometimes hard to distinguish from Gneiss. 

Diabase or Trap. — Crystalline, coarse to fine, dark gray or black. Among 
the crystals, black minerals such as Hornblende predominate. Feldspar, 
light colored, is in small quantity. Often so fine grained that separate 
crystals cannot be distinguished without lens. 

Quartz-Porphyry. — Dark gray, reddish, or pinkish “ground mass,” in which 
scattered crystals of Quartz or Feldspar may be distinguished (Quartz, color- 
less or whitish; Feldspar, usually straw colored or flesh-colored, latter with 
rectangular outline, former, usually irregular). 

Amygdaloid. — Dark colored, often black, and fine grained, with “almond- 
shaped” bunches of light colored substances (usually the minerals Quartz 
and Calcite). An old lava, in which steam-bubble cavities have been filled up 
by deposits from percolating waters. 

Sedimentary Rocks. 

(Originally deposits of sediment, or organic substances, or chemical pre- 
cipitates, under water, hardened by pressure of overlying sediments, or by 
heat, or by some natural cementing substance.) 

Limestone or Dolomite. — Gray or buff-colored, varies from coarse crystalline 
texture to very compact fine grain. Limestone is largely lime carbonate, and 
unless very impure will effervesce when dilute hydrochloric acid is applied. 
In Dolomite there is some carbonate of magnesium, and other impurities, 
and it does not commonly respond readily to this chemical test. It is not 
very hard, and will scratch with a knife. Formed chiefly by the deposition 
of ground-up shells and skeletons of marine animals, together with some 
mud or ooze, frequently rich in fossils. 

Chert. — Harder than steel, flinty; where freshly broken it has a sharp frac- 
ture and dull greasy luster, dull yellow, gray, or brown, common in lime- 
stone both as irregular lumps or “nodules” and in thin beds. In part, at 
least, derived from siliceous sponges which were buried by sediments on the 
sea floor. 

Sandstone. — Grains of sand bound together into a gritty, often crumbly 
mass; color depends lately upon the cementing substance; red, yellow, or 
brown, if the cement is ii n oxide; white if it is silica; grains largely Quartz; 
sometimes flakes of Mica. 


38 


THE DES PLAINES VALLEY. 


[BULL. NO. 11 


Shale . — Hardened clay or mud greenish gray, dark brown, or black; soft, 
easily scratched with a knife; yields odor of clay when breathed upon, be- 
cause of presence of kaolin. 

Quartz. — White, except as stained by impurities; too hard to scratch with 
steel; glassy where broken. Pebbles are fragments of Quartz veins, or 
fillings of fissures in other rocks by deposits of silica from solution. 


Metamorphic Rocks. 

(Originally either Igneous or Sedimentary rocks, greatly altered by effects 
of compression or deep burial in the earths’ crust, or in some cases by the 
extent of the cementation.) 

Quartzite . — Very hard, fine crystalline, sugary texture; white, pinkish, 
purplish, or dull grayish; formerly a sandstone; re-crystallized by addition of 
silica deposited from solution. 

Slate . — Formed from Shale by compression. Harder than Shale, with well 
defined plane of splitting or cleavage. 

Marble . — Like Limestone, but distinctly crystalline, and somewhat harder. 
A re-crystallized Limestone. 

Gneiss . — A banded, crystallized rock, often coarse grained; separate crystals 
of such minerals as Quartz, Feldspar, Hornblende, and Mica, arranged in 
more or less definite bands, and thus distinguished from Igneous rocks. 
Lighter varieties, with much Quartz and Feldspar, resemble Granite; darker 
ones often largely composed of pinkish Feldspar and black Hornblende and 
Mica. Most Gneisses seem to have been formed from Igneous rocks, under 
great pressure. 

In the following table is the number of pebbles of various kinds of rock 
identified from a hundred bits of rock that were taken indiscriminately from 
a cubic foot or so of bowlder clay or ice-laid drift at two different places, 
both of them in an exposure of till at the east end of McEnty street, in 
Joliet: * 


* 

First 

collection. 

Second 

collection. 

• 

Limestone 

77 

78 

Sandstone 

8 

10 

Shale 

2 

1 

Quartzite 

1 


Diabase 

9 

5 

Granite 

3 

6 


• 



Evidently the limestone, most of which has presumably come from close 
at hand, forms about three-quarters of the stony material. The sandstone and 
shale probably came from the Potsdam and Cincinnati formations, to the 
north and northwest, though some may have come from the Devonian rocks 
which underlie Lake Michigan. The diabases and granites, and some of the 
quartzites, came from northern Wisconsin or beyond, a distance of at least 
250 or 300 miles. 


The stratified drift . — As regards the variety of rocks represented 
among its c-onstitutent bowlders, pebbles and smaller particles, the strati- 
fied drift resembles the till. The material that composes the two classes 
of drift were picked by the ice from a common collecting ground, and 
because of the vast extent of this collecting ground thev show the re- 
markable variety indicated in the last few pages. The features peculiar 
to stratified drift which distinguish it from till, are those which have 


l 


* Pebbles identified and counted by Mr. Charles E. Decker. 


goldth wait . J GLACIAL AND INTER-GLACIAL DEPOSITS 




been effected by the wearing and sorting action of water. While the ice 
sheet melted, some of the rock waste upon and within it found its way 
into outflowing streams, which washed the debris along, sifting out the 
finer and depositing the coarser particles in such places and at such 
times as the strength of the currents was over-taxed. Such deposits, 
therefore, are in layers, because of the repeated changes in the strength 
of the currents. Coarse gravel, fine gravel and sand occur in successive 
beds, in the order of their deposition. The pebbles have been more or 
less completely rounded, and are as a rule arranged flat side down, 
although where coarse gravel deposits have been hurriedly made the 
constituents are sometimes poorly arranged, and the stratification may 
be obscure. The bedding is usually nearly horizontal — the attitude of 
a stream bed, but separate layers in a single horizontal stratum may be 
strongly inclined — a condition known as “cross bedding." (See Plate 
4, A.) This peculiar stratification, in many instances, marks the for- 
ward growth of a sand bar or a delta. The slanting layers represent suc- 
cessive positions of the sloping front of the deposit, as it was advancing. 
After a large mass of these inclined beds has been laid down, the' cur- 
rents mav shift in direction or increase in strength, in such a way that 
the upper part of the deposit may be cut away as if bevelled and a new 
layer mav be formed above the horizontal surface of planation, with its 
beds inclined in another direction. Where currents are very erratic or 
tumultuous, as was evidently the case near the border of the ice sheet, 
the cross bedding is still more irregular. Xo horizontal planes of bedding 
appear, but the deposit is a mass of lens-shaped pockets of gravel and 
sand, dipping in various directions — This condition is known as “flow 
and plunge” structure. Examples of both sorts of cross bedding can 
be seen in Overholster’s gravel pit, near the south end of Logan avenue 
in Joliet (See Plate 4, A.) 

Stratified drift is, for the most part, distributed along lines of initial 
depression, for the waters discharging from the ice sheet seek the* 
lowest ground; hence it happens that the thickest deposits of glacial 
gravels in this district (if we except older deposits which were buried 
by the last advance of the ice) are to be found along the Des Plaines 
vallev and the valleys of the larger tributaries, and around the low Chi- 
cago plain, which, was formerly covered bv a great lake. 

Large deposits of stratified drift occur about Joliet. On the south- 
east side of the city a high ridge of gravel starts in at the bend of the 
Michigan Central railroad near Hickory creek, and runs south and south- 
west. across Powell avenue. On its southeast side the gravel deposit 
formerly extended off with gentle slope to the base of the moraine ; but 
the gravels have been widely excavated for railway ballast. Fresh cuts 
near Powell avenue show exceedingly coarse gravel with occasional 
bowlders. This greater coarseness of gravel, together with the steep- 
ness of slope on the northwest side of the deposit, in contrast to the 
gentle slope towards the east, suggests that the gravels were washed out 
from a tongue of ice which lingered in the vallev while the main border 
of the ice was on the Valparaiso moraine to the east, and which at length 




40 THE DES PLAINES VALLEY. [hull. no. 11 

melted away, allowing the gravels in contact with it to slip down, form- 
ing a steep slope. The form of the ridge varies greatly as it runs 
south, gaining at times a steep slope on both sides. In places, however, 
the steepness of the slopes seems clearly due to lateral erosion of Hickory 
creek on the one side or of the old outlet on the other; for the Des 
Plaines valley for a time was occupied by a large river which discharged 
from Lake Chicago. It may be that all these steep slopes are to be ac- 
counted for thus, by erosion, rather than by previous contact with the 
ice edge and the removal of that support. 

At Overholser’s pit, near Linden heights, is a fresh forty foot sec- 
tion of cross-bedded sands and gravels, which here form the outer border 
of the main Valparaiso moraine. The cross-bedded layers (as seen 
in Plate 4, A) show a rather persistent dip towards the west, indicating 



Fig. 8. Diagram showing the border of the ice resting against the outer 
morainic ridge of the Valparaiso system, near Joliet, Lockport, and Romeo. Four 
transverse passages are occupied by glacier-fed streams, and are being aggraded 
with gravel. The passage nearest the foreground later became the course of the 
Chicago outlet, and finally of the Des Plaines river. The one next to the left is 
the “big slough” north of Joliet. 

that the growth of the deposit was to the westward. The relations to 
the Valparaiso moraine suggest that this is part of a smooth fan-like 
deposit or “frontal apron,” washed forward from the ice while it lay 
against the moraine. The plain which separates the main ridge from the 
west ridge of the Valparaiso morainic system south of Joliet may be the 
-surface of a part of the same frontal apron. The deposit is of special 
interest because it resembles in structure a much older gravel deposit, 
the Joliet conglomerate described later. 


STATE GEOLOGICAL SURVEY, 


BULL. NO. 11, PL. 4 



A. 


Stratified drift at 


Overholser’s 


pit, 


Joliet. 



B. Exposure of Joliet conglomerate near Spring creek 



































COLDTH WAIT.] GLACIAL AND INTER-GLACIAL DEPOSITS. 


41 


The chief deposits of gravel, which took place in the valleys which 
were the main lines of drainage while the ice was melting, are called 
“valley trains.” The lies Plaines valley from Lemont down past Joliet 
to Channahon, evidently received a thick deposit of this outwash, for it 
was the main line of escape for the glacial waters with their over-burden 
of rock waste. The original valley floor was built up by these deposits 
locally some fifty feet. At the same time, tributary streams built branch 
valley trains. This was the case in the valleys of Long run, Fraction 
run, Spring creek and Hickory creek (See Plate 5, A.) This process is 
illustrated in Figs. 8 and 9. At a later time, when the ice sheet had 
withdrawn from the Valparaiso moraine, the over-loaded ice-fed stream 
in the Des Plaines valley was replaced by a river which issued from a 



east side of the Valparaiso moraine. Aggrading rivers from it pass down the 
valleys of Hickory creek, Spring creek, Fraction run, Long run, the “Sag,” and the 
Des Plaines valley. Distributaries occupy the transverse passages in the outer 
ridge, in the foreground. 

great ice-front lake, and which, free to gather up a load for itself, exca- 
vated a deep, wide trench in the valley filling, carrying away most of the 
deposits. Only a few scraps of the old valley train were left as terraces, 
e. g., opposite Lockport, and three miles west of Joliet, or as flat-topped, 
island-like mounds in mid-channel, like Flathead mound between Joliet 
and Channahon. These are mentioned more particularly on later pages. 
It is of interest, however, to note here that in certain places (e. g., in the 
outwash terrace opposite Lockport) the pebbles in the gravel have been 
coated over with a white crust of carbonate of lime, left by percolating 
water. Sometimes this film of lime carbonate is an eighth of an inch 
thick, and serves to bind a few pebbles together (See Ho. 3, Plate 3) : 
hut in no place has cementation progressed far. 


42 


THE DES PLAINES VALLEY. 


[BULL. NO. 11 


Along each side of the I)es Plaines valley above Lemont, gravels are 
to be found where artificial cuttings have been made. At Kellar's brick- 
yards, a mile north of Willow Springs, a freshly cut bank sixty feet high 
shows stratified gravels and sands beneath ten to twenty feet of till. The 
gravels there may belong to a distinctlv older interval than that which 
followed the last stage of glaciation. 

The stratified gravels exposed in the upper part of the Des Plaines 
basin, on and near the Chicago plain, are ehiefiv in the form of beach 
ridges, spits, and other shore deposits of the extinct glaciaj, Lake Chi- 
cago. While to some extent they may be regarded as stratified drift, 
they were formed for the most part long after the ice had withdrawn 
from our district, and its influence on them was quite indirect. Like 
the gravels in aprons and deltas, they often show cross bedding. 


THE JOLIET CONGLOMERATE. 

At several places in the vicinity of Joliet, there are exposures of gravel 
firmly cemented by carbonate of lime into a conglomerate. Judging 
from its composition and its relations to the overlying Wisconsin till, 
this conglomerate represents one of the earlier interglacial epochs. The 
largest and most instructive exposure so far observed is at the east end 
of McEnty avenue, near the old wire mill, and on the north side of 
Spring creek (Plate 4, B.) The cemented gravels here are immediately 
overlain by late Wisconsin till. Another outcrop, better known, but 'of 
less significance, since it is buried by outwash gravels rather than till, 
and thus looks at first sight like a locally cemented mass of the late 
Wisconsin gravel deposits, occurs at the bend of the Michigan Central 
railway, a short distance west of the pumping station in Joliet. The rock 
also outcrops nearby on Cass street. A large amount of the conglomerate 
was excavated at this place a number of years ago. The ledge that re- 
mains, close beside the tracks, is some ten feet high. In the bed of Bush 
creek, in Peed’s woods, the surface of the conglomerate is seen where the 
stream is trimming back a spur at the side of its ravine. On the map, 
Plate 7, “CgA indicates this outcrop of _ the conglomerate. It looks as 
if the rock belonged under the till of which the bank is composed. 
The conglomerate here is of finer texture than usual, but in other re- 
spects seems to be like that at other exposures. As only a thin layer 
is exposed here, one cannot judge either of the extent or of the average 
structure of the entire mass that may underlie the bowlder clay in the 
bank. This exposure is about three and a half miles southeast of the 
one near Spring creek. In a railway cut on the Elgin, Joliet and Eastern 
railway, near Powell avenue, in the extreme southeast part of Joliet, 
ten feet of till covers a coarse gravel deposit which is in places well 
cemented with carbonate of lime and limonite (hydrous oxide of iron). 
Ko where else has a limonite cement been noted. This rock is doubtless 
the same formation as those mentioned elsewhere. 

Another outcrop appears in the bluff on the east side of the outlet valley 
just north of Lockport, close beside the Chicago and Joliet trolley line. 


state geological survey, 


BULL. NO. 11, PL. 5 



A. Outwash terrace on Spring creek. 



B. Fraction run above Dellwood Park 




GOLDTHWAIT.] GLACIAL AND INTER-GLACIAL DEPOSITS. 


43 


This shows eight feet of the rock, with the lower limit not exposed. This 
exposure is about seven miles north-northeast of the Bush creek outcrop, 
and four miles north of the one at Spring creek. Talus, which appears 
in the bluff still farther north, near Borneo, looks suspiciously like the 
cemented conglomerate. Reports of a “hardpam underlying the till 
along the line of the Chicago drainage canal, a mile or so east of Sum- 
mit 1 suggest that the conglomerate covers even a wider area than that 
marked by the outcrops just mentioned. Doubtless as further search 
is made the known extent of the formation will be greatly increased, as 
well as the understanding of its origin. The following data concerning 
the Spring creek exposure was collected by Mr. C. E. Decker. 

The conglomerate outcrops in a large , artificial exposure beneath the 
till of the Valparaiso moraine (See Plate 4, B.) From the base of the 
till to the bottom of the excavation the exposure of cemented gravels is 
about eighteen feet. The overlying till is very compact, and chiefly 
composed of fine rock flour, with a moderate supply of small stones, 
some of which are striated and most of which are sub angular. The 
stones of the till, classified according to composition and given in per- 
centages, has already been given. -The till is separated from the under- 
hung conglomerate by a well defined plane of unconformity. The till 

CD CD t/ J. 1/ 

immediatelv above the unconformity shows no signs of cementation. 
The surface of the conglomerate is smooth, though locally marked by 
semi-parallel ridges an inch or two across and rather faint in expression, 
yet distinct enough to convey the impression that they may be marks of 
the late Wisconsin ice sheet. They trend northeast-southwest. The 
surface does not appear to have been striated, however, nor do there ap- 
pear to be any ridges of the shalv matrix of the conglomerate in the lee 
of projecting pebbles, where such ridges might be expected to develop. 
At the top of the' cemented section is a dense shalv fever of rock, buff 
colored and thinly laminated in a horizontal plane. It seems never to be 
more than an inch or two thick. Beneath it come about six feet of hori- 
zontally bedded gravels, fine at the very top and moderately coarse be- 
low. The uppermost three inches are well cemented; below that is a zone 
of about a foot and a half of looselv bound gravels, and then again the 
firmly cemented material. Most of the pebbles in these horizontal 
beds are well rounded, although many are sub-angular. Below this six 
foot stratum come four feet of cross-bedded gravels of much coarser 
texture; more than one-half the pebbles in this are sub-angular to an- 
gular, and all are arranged flat side down on the inclined beds, which 
dip 25 degrees toward the southwest. They may be seen in the photo- 
graph, PI. 4, B. Beneath this is a confused mass of angular blocks, 
cobbles and coarse gravel, containing bowlders two feet in diameter. 
The interstices are not all filled, leaving the gravel with an open-work 
structure. No bedding could be discovered. A large majority of the 
fragments of rock are angular, but none were found with striated sur- 


l Geological Atlas of the United States, U. S. Geol. Surv., Chicago Folio No. 
81, p. 7. 


44 


THE DES PDAINES VALLEY. 


[BULL. NO. 11 


faces. It should be said, also, that the degree of cementation varies 
locally in a horizontal direction as well as in a vertical. This gives rise 
to irreghlar projections and re-entrants in the cliff exposure. 

A careful study was made of the pebbles in the conglomerate in order 
to determine the variety of rocks represented and the proportion of each. 
Without any choice as to - size, one hundred pebbles were selected at 
random from a small space on the face of the cliff, and the pebbles were 
identified and counted. This was done at three places, with the results 
which follow. Since each set includes 100 pebbles, the figures for each 
kind of rock represent percentages. 


Position. 

Limestone 

Chert. 

Sandstone. 

Granite. 

Diabase. 

Half way up cliff 

83 

7 

3 

4 

3 

At same level, within 10 feet of No. 1 

87 

6 

3 

2 

2 

Near top of cliff, and 50 feet aw’ay. .. 

88 

2 

5 

4 

1 


The table shows a pretty close agreement in the three counts, in making 
the limestone 'content about 86 per cent of the whole. The limestone and 
the chert are probably almost wholly derived from the Niagara limestone, 
the bed rock. Apparently, then, about 80 or 90 per cent of the gravels 
are of local derivation. The percentage of crystallines (chiefly granites 
and diabases, although some are probably to be regarded rather as 
gneisses) is very small, less than five per cent. But their igeneous char- 
acter indicates a remote source for at least a part of the deposit. The 
crystallines probably do not exist in place nearer than the highlands of 
northern Wisconsin, some 300 miles away. All the large cobbles, bowld- 
ers and angular blocks seemed to be of limestone. The granites and dia- 
bases were well rounded pebbles of medium and small size, as would be 
expected from their having journeyed many times as far as the others. 

The outcrop of the Joliet conglomerate at Lockport shows about the 
same proportions of different sorts of rock, with perhaps a slightly larger 
number of granite and diabase pebbles, say 5 to 10 per cent. No coarse, 
angular material is exposed there at the base. The rock is cemented just 
as firmly as at Spring creek. 

It may be said that the percentage of local fragments (limestone and 
chert) in the cemented gravels is about the same as in the late Wisconsin 
till at the same locality for the latter shows about 78 per cent, as against 
the 86 per cent in the older material. The till was found to contain about 
12 per cent of crystalline pebbles — a somewhat larger number than were 
found in the conglomerate at Spring creek. 

On the basis of these facts, some conjectures may be formed concern- 
ing the origin of the Joliet conglomerate. That it is a glacial gravel de- 
posit seems clear from the variety of rocks represented in the pebbles. 
No such collection would be at all likely to be made by any conceivable 
river or lake in this district. That it is older than the late Wisconsin 
drift is indicated by the fact that it is unconformably covered bv the till 
of the Valparaiso moraine. It is of some significance also that the bed- 
ding of the conglomerate, close to the surface, shows no sign of folding or 


GOLDTHWAIT.] GLACIAL AND INTER-GLACIAL DEPOSITS. 45 

other disturbance. One would be inclined to infer that the gravels were 
already cemented when they were over-ridden by the ice, else their strati- 
fication would have been disturbed by pressure. The glaciated appear- 
ance of the surface of the conglomerate and the unaltered condition of 
the overlying till argues likewise for pre- Wisconsin cementation. Judg- 
ing from the advanced state of cementation in which a well-nigh solid 
rock has been formed out of gravels, a time interval of very considerable 
length must have elapsed after the gravels were deposited and before 
the late Wisconsin glaciation. If the conglomerate is compared with the 
more recent outwash gravels, even those for instance in the outwash 
terrace opposite Lockport which show more than the usual amount of 
cementation, the alteration of the former obviously represents several 
times the amount of alteration of the latter, and we may infer that it 
is several times as old. Turning now to the conjectured time relation 
for the several glacial epochs , 1 we find that the interval since the early 
Wisconsin is estimated to be about twice the post-glacial interval, the 
one since the Iowan four times, since the Illinoian eight times, since 
the Kansan sixteen times, and since the Jerseyan a very much longer 
time. It seems probable, then, from the extent of cementation (and all 
that, perhaps, before the overlying till w^as deposited) that the Joliet 
conglomerate is 'at least as old as the Illinoian drift. 

o 


l See Chamberlin and Salisbury, “Geology,” vol. 3, pp. 413-414. 


THE DES PLAINES VALLEY. 


[BULL. NO. 11 


46 


CHAPTER V. 


PHYSIOGRAPHIC HISTORY OF THE LOWER DES PLAINES 

RIVER. 


GENERAL DESCRIPTION. 


The lower Des Plaines river follows a flat-floored, steep-sided valley, 
which was cut down across the broad Valparaiso morainic system by 
the large river that drained the Great Lakes during the closing stages 


of the glacial period. This valley, inherited by the Des Plaines from 
the ancestral river, the outlet of Lake Chicago, far exceeds the dimen- 
sions appropriate to the streams present size and sculpturing ability. 
With a somewhat devious course, the channel of the old outlet leads from 
the lake plain near Summit (See Fig 10) westward and southeastward 
through the broad upland belt of the Valparaiso moraine, uniting just 
beyond its outer border with the Kankakee river, on the broad, low 


plain of the “Morris basin." Between Summit and Lemont the river 
flows by a directlv transverse course through the main moraine, and 
gathers scarcely any drainage except the direct run-off from the high 
bluffs on either side of the valley. But beyond Lemont its course is 
southward along the outer border of the main moraine, from which it 
receives a large number of tributary creeks. Of these, Long run. Spring 
creek and Hickory creek drain considerable areas in the interior of the 
moraine, and widen the drainage basin of the Des Plaines over ten miles 
on the east side. Beyond Joliet the outlet valley opens on the broad 
plain which surrounds the junction of the Des Plaines, Du Page and 
Kankakee rivers. The Du Page joins the Des Plaines so close to its 
mouth that physiographicallv it might as well be considered a direct 
tributary of the Illinois. Its basin is enclosed bv the Minooka till ridge, 
on the west, and an outlying ridge of the Valparaiso morainic system 


on the east. 


In addition to these larger features, certain details of geologic struc- 
ture and physiographic form along the lower Des Plaines demand ex- 
planation — Among these may be mentioned : The relation of the extinct 
outlet to the bed rock, which rises to a considerable height in the bluffs 
at two places (Lemont and Lockport) : the high level terraces of gravel, 
conspicuous at several points below Romeo, and terminating near the 
bead of the Illinois at Channahon ; ,a lower terrace of rock on both sides 
of the valley near Lockport, and the terraces of tributary streams. 


goldthwait . ] HISTORY OF THE LOWER DES PLAINES. 


47 


In order to understand the physical features of the valley, we shall 
follow the development of successive moraines and outwash deposits 
along the retreating ice-border, the formation and the gradual extinc- 
tion of ice-dammed lakes, and the steps in the cutting down of the 
great Chicago outlet. 


DEPOSITION OF TIIE EARLY WISCONSIN DRIFT. 

The early Wisconsin moraines . — The outline of the border of the 
Wisconsin ice-sheet in Illinois at the time of its greatest extent is 



Fig. 10. Map of the lower Des Plaines river, showing- towns, tributaries, and 
distribution of drift. Rv, Riverside ; S, Summit ; Wi, Willow Springs ; Lm, Lemont ; 
Ro, Romeo : Lk. Lockport ; J, Joliet ; N. L, New Lenox : C. Channahon ; Wh. 
Wheaton ; Na, Naperville ; Au, Aurora ; 1, Salt creek ; 2, Chicago river ; 3, Flag 
creek ; 4, Calumet river ; 5, Long run ; 7, Fraction run ; 8, Spring creek ; 9, Hickory 
creek; 10, Sugar creek; 11, Jackson creek; 12, Prairie creek; 13, Rock creek; 14, 
Dupage river; 15, Ausable creek; 16, Fox river; 17, Buffalo creek; 18, Isle la 
Cache creek ; 19, Mink creek ; 20, Crystal run. Drift plotted from LT. S. Geol. Surv., 
Monog. 38, by Leverett, with minor changes. 


shown on the sketch map (Figure 6). Its position is marked out by the 
broad Shelbyville moraine, a continuous belt of drift built up along 
the ice margin, when, for a considerable time, the backward melting of 
the ice was more or less evenlv balanced bv forward motion, and the 


48 


THE DES PLAINES VALLEY 


[BULL. NO. 11 


ice border remained almost stationary. When, through the intiuence of 
climatic change, the melting of the ice-front came to exceed its advance, 
the ice border was shifted northeastward. The Illinois lobe of the ice 
sheet contracted to lit the Lake Michigan basin. The withdrawal was 
slow and frequently interrupted by short returns of severer climate, 
during which the ice border became stationary, or even re-advanced 
slightly. Each time it halted it built a new morainic ridge, whose size 
is roughly proportional to the duration of the period of re-advance* 
Between the moraines the drift was spread out in gently undulating 
plains of till. 

One of the most conspicuous of these crescentic moraines, the Mar- 
seilles moraine, lying just east of the Fox and Vermilion rivers, forms 
the semi-circular rim of the Morris basin — a broad, flat plain on whose 
eastern border the Des Plaines and Kankakee rivers’ unite to form the 
Illinois. 

The lake in the Morris basin. — The retreat of the ice border from 
this moraine seems to have left a lake of considerable size in the Morris 
basin, which found its discharge over the lowest point on the morainic 
rim, near Marseilles. Beaches built along its shores indicate that its 
level was fully sixty feet above the river, or G50 feet above the sea. 
As the outflow cut its channel down through the moraine, it encountered 
the underlying bed rock at an altitude of about 560 feet. This probably 
explains the fact that the lake level remained stationary long enough 
for distinct beaches to be formed. Indeed, as will presently be explained, 
there is good reason to suppose that the lake was still in existence at 
the 500-foot level when the ice was making the Valparaiso moraine, 
ten or fifteen miles farther east. 


DEPOSITION OF THE LATE WISCONSIN DRIFT. 

The Minooka till ridge . — Following the development of the lake in 
the Morris basin, and before the construction of the next system of mor- 
aines occurred a shifting of the ice lobes in northwestern Indiana, as 
a result of which the late Wisconsin moraines overlap the earlier mor- 
aines in transverse position (See Figure 6). There was evidently a 
sudden growth of the Erie and Saginaw lobes of the continental glacier, 
a growth which pushed them westward over the territory which had 
formerly been occupied bv the Lake Michigan lobe. The discordant 
relation of the two sets of moraines and the somewhat subdued topo- 
graphy of the earlier set have led to the separation of the Wisconsin 
epoch into an early and a late Wisconsin stage. In the district we have 
to consider, the Marseilles moraine is the last of the early Wisconsin 
moraines, and the Minooka till ridge ; a small morainic ridge forming 
the east side of the Morris basin, is the first of the late Wisconsin mor- 
aines. 

The Minooka till ridge, from the head of the Illinois river, where it 
is from 100 to 110 feet high, northward for fifteen to twenty miles, is 
“ a single smooth ridge on whose crest and slopes there are few swells 
exceeding ten feet in height.” It is scarcely two miles wide. “The 


GOJLDTHYVAIT.J 


HISTORY OF THE LOWER DES PLAINES. 


49 


ridge is crossed by two valley-like depressions, which unite near its 
western edge, in Sec. 13, T. 30, R. 8 E., and drain west into An Sable 
creek. These are cut down to the level of the plain on the east side 
of the ridge. They apparently were formed by the discharge of water 
from the ice margin or ponded between the ridge and the receding ice 
front.” 1 

South of the river onlv a few low, broken mounds and ridges of 

J O 

drift mark the continuation of the ice border at this stage. 

The Valparaiso morainic system and its outwas/i . — The next station- 
ary position of the ice border was one of long duration, resulting in the 
building of the highest and broadest of the morainic belts with which 
we are here concerned — the Valparaiso morainic system. This is a 
great U-shaped belt of drift that encircles the south end of Lake Mich- 
igan, with its course about twenty miles back from the lake. Lt is not 
a single ridge like the moraines just described, but a belt in which, 
in our district three parallel belts of morainic hills, separated by 
two narrow plains of drift may be distinguished. The other ridge 
separates the Du Page and Des Plaines valleys north of Joliet. It is 
itself separated from the middle morainic belt southeast of Joliet by a 
fainting undulating plain, which narrows as it approaches the State line, 
allowing the outer and middle belts to merge into one. 

The outer ridge, north of Joliet, is cut transversely by three well de- 
fined channels, or scour-ways (as shown in Figure 10). One of these, 
crossed by the Plainfield road three m iles northwest of Joliet, is a broad, 
tlat-tloored sag nearly half a mile wide and four miles long. It is 
occupied by a marsh, which drains eastward through Crystal run and 
westward through Pock run. Moderate slopes on either side lead to the 
morainic upland. Tie floor is immediately underlain by bed rock, 
which is shown in small quarry diggings a mile east of the Plainfield 
road. At its eastern end, the floor of the sag finds continuation in a 
rock terrace of the Des Plaines valley above Joliet, near the Sprague 
school house., A few feet above the marshy floor, on either side, is a 
faintly defined sheet of gravel, which passes into a distinct terrace at 
the Des Plaines valley to the eastward. From these gravels and similar 
deposits in the Des Plaines valley at several points below Romeo it ap- 
pears that the three sloughs north of Joliet, and the I )es Plaines valley 
just below Joliet, were lines of discharge of glacial drainage while the 
ice rested against the outer belt of the Valparaiso moraine. Figure 8 
illustrates this condition of things. As the ice withdrew to the position 
of the middle belt, the inter-morainic depression between Joliet and 
Romeo gathered the discharge of heavily loaded streams from th* 
outer slope of the new moraine (See Fig. 9). Long continued aggrad- 
ing with coarse gravels raised the level of the inter-morainic valley up 
to and above that of the transverse sloughs. Water from the ice then 
flowed through them and deposited trains of gravel or “outwash.” At 
a still later time, after fhe ice had withdrawn from the Valparaiso 


" Leverett. Monograph 38, U. S. Geol. Surv.. p. 319. 


50 


THE DES PLAINES VALLEY. 


[BULL. NO. 11 


moraine and the outlet of a newly formed Lake Chicago found its 
way down the line of outwash, aggradation gave way to degradation. 
The floors of the transverse sloughs were reduced by the overflow from 
the main valley. The three sloughs north of Joliet were only slightly 
lowered before the streams encountered bed rock. The one in which the 
rock lay deepest below the surface (that south of Juliet) was degraded so 
much the more rapidly that it became the sole line of discharge of the 
outlet river, while the three rock-floored passageways north of Joliet 
became sloughs. During the lapse of several thousand years marsh 
growth has built up the floors of these sloughs and running water has 
somewhat smoothed down their side slopes. 

The surface of the main belt of the Valparaiso moraine is more typi- 
cally morainic than the one which passes west of Joliet, although its 
irregularity is nowhere so pronounced as to exhibit steep slopes compar- 
able to the “kettle moraine” of Wisconsin or the terminal moraines of 
many other places. It is composed of numberless knolls and basins. 
So subdued are they that the eye hardly appreciates the range of un- 
dulation, which often amounts to 25 feet. Over the greater part of the 
moraine the knolls show a tendency to elongation parallel to the mor- 
ainic belts, but on the inner border they seem rather to be elongated in 
the direction of ice motion. On account of the compactness of the 
bowlder clay of which the moraine is largely composed, little ponds and 
marshes are of frequent occurrence in the depressions of the moraine, and 
peat bogs of considerable thickness have formed in the deeper de- 
pressions. The cause of the rolling surface of the moraines has been 
explained on previous pages. 

Between the middle and the east belt of the Valparaiso morainic 
system, is a rather well defined plain. Several large streams which 
join the Des Plaines between Romeo and Joliet head here in broad 
marshes : Long run and Spring creek in the township of Orland, and 

Hickory creek near Tinlev park. The lower courses of these tributary 
valleys, from the points where they cross the middle of the morainic 
belt down to their junctions with the Des Plaines, were lines of aggra- 
dation for glacial streams during the whole time the middle moraine 
was being deposited (See Pig. 9). Together with the inter-morainic 
depression into which they ran, they were heavily aggraded with coarse 
outwash gravels. Patches of the old valley train of Hickory creek occur 
all the way from Hew Lenox down to Joliet, and patches of the valley 
train of Spring creek occur below Hadley. Where the valley trains head 
on the moraine, they partake of the rolling surface which characterizes 
the ice-laid drift, for these gravel deposits at the immediate border of 
the ice were subject to just the same causes of irregular concentration 
and re-arrangement as the moraine itself. But down the valleys their 
surfaces become as smooth as the flood plains of the present streams. 
East of Joliet a remnant of the valley train of Hickory creek forms a 
conspicuous terrace near the old red mill. Its gravelly constitution may 
be seen below the iron bridge, where the river is freshly trimming the 
terrace, or at the gravel pits beside the Rock Island railway, just west 
of Shaw’s brick yards. On Spring creek, above the old wire mill, fine 


G OLDT H wait.] H1STORV OF THE LOWER DES PLAINES. ' 51 

•J 

terraces of the valley train stand 35 feet above the present flood plain 
(Plate 5, A.) On the north side of the valley fresh cuttings show well 
stratified gravel, frequently cross-bedded, the constituents varying in 
size from cobblestones to fine sand. A natural section occurs a few hun- 
dred yards east of the wire mill, where the creek is trimming away the 
bluff. At the base of this section the compact, blue bowlder clay may 
be seen beneath the gravels. 

The upper portion of the broad valley now followed by the Des Plaines 
between Mount Forest and Eomeo, as well as the “Sag,” which joins 
it above Lemont, were doubtless transverse depressions, like the valleys 
of Hickory creek and Spring creek, and were deeply aggraded with .out- 
wash gravels. They were the head of a. system of valley trains, as in- 
dicated in Fig. 10. A main line of discharge, to which they were tribu- 
tary, was the longitudinal depression between the middle and west 
morainic belts. The floor of this depression was evidently built up 
so high with gravels that the aggrading stream overflowed all four passes 
through the west ridge. At the upper end of the pass, near the Sprague 
school, a mile north of the end of the Hickory street car line, the out- 
wash gravels form a flat terrace on the west side of the main valley. 
This is but a small scrap of the flat-topped valley train which once 
filled the entire valley. The heavy cobbly constitution is revealed in 
a pit north of Frank Sprague’s house, where the road to Coyne's station 
rises from a rocky bench up to the outwash terrace. Another flat-topped 
remnant of the valley filling is on the west side of the valley, opposite 
Lockport, where the road to Plainfield leaves the valley floor. The flat 
surface of the terrace stretches westward several hundred yards, to the 
gently undulating slope of. the moraine. A cut by the roadside shows 
the gravels to be locally coated and cemented with carbonate of lime. 
The incrustation on the pebbles attains a thickness of over a tenth of 
an inch (See Plate 3, Ho. 3). 

The height (above sea level) of the outwash terrace at Lockport is 
620 feet; near the Sprague school, 603 feet. The valley filling ex- 
tended south and west past Joliet to Channahon, where it took the form 
of delta-like flats at the border of the lake which still occupied the 
Morris basin. Most of the filling was removed when Lake Chicago came 
into existence, and its great out-flow following the main line of glacial 
drainage, excavated for itself the present deep valley. Only occasional 
scraps were left, usually as terraces on the valley sides, like those de- 
scribed above. 

On the north side of the Des Plaines valley, a few miles below Joliet, 
the outwash terrace is broad and conspicuous. The upper road to Chan- 
nahon follows it for a few miles. Out in the middle of the vallev is a 
great island-like mound known as “Flathead,” which marks the former 
extension of the outwash terrace over the whole valley. This, the 
largest remnant of the valley train, rises about eighty feet above the 
water. It may have escaped erosion by the outlet river because of a 
protecting ledge of bed rock; for the rock rises in places nearly to the 
top of the mound. Joliet mound, near Rockdale, was also an isolated 
patch of the valley train, but it has been artificallv destroyed. 


THE DES PLAINES VALLEY. 


]BULL. NO. 11 



It may be remarked here that the four transverse sags, or passage-, 
across the outer ridge of the Valparaiso moraine lie about in line with 
four important valley trains from the middle morainic belt (Figs. 0 
and 10). The slough between Isle la Cache creek and Plainfield lie- 
opposite the transverse valley of the outlet at Lemont. The slough at 
the head of JVIink creek is nearlv in line with Long run at Romeo. The 
slough above Crystal run lies opposite Fraction run, and the tranvers * 
valley of the Des Plaines at Brandon's bridge is a sort of continuation 
of the united Hickory and Spring creeks. While this relation of valley- 
may be purely accidental, it suggests that the position of the main 
rivers at the ice border was not much changed during the melting back 
of the ice front from the west belt to the middle belt of the moraine. 

The east belt of the morainic system is separated from the middle belt 
north of the “outlet" by the valley of Flag creek and Salt creek. At 
Mt. Forest island and farther south its relation to the middle belt is 
more intimate; yet in places, especiallly- near Tinley park, the two 
upland belts are divided by a smooth plain of considerable width. The 
contrast between the plain and the rolling morainic belts is well seen 
along the Rock Island railway. On Mt. Forest island, east of Willow 
Springs, the topography of the moraine is unusually rough. The knobs 
and hollows have a range of over fifty feet, and ponds arc abundant. 


EXCAVATION BY THE OUTLET OF LAKE CI1ICAOO. 

(jfhniwood staff e — Excavation of a french in the ralleif train . — As the- 
great lobe of the ice sheet melted back from the Valparaiso moraine 
there slowly opened up between the moraine and the ice a crescent- 
shaped lake, known as Lake Chicago (Fig. 11). The waters of this ice- 
dammed lake found their escape across the moraine through the con- 
verging arms of a V-shaped depression which led westward past Lemont 
and down the broad longitudinal valley between the main ridge and the 
outer ridge of the Valparaiso morainic system. No precise reason can 
be given for the presence of the two initial sags in the moraine which 
determined the two forks at the upper end of the outlet, on either side 
of AI t. Forest island. It should be recognized, of course, that accumula- 
tion of drift along the ice border was quite irregular, that the moraine 
was locally very weak, and that occasional transverse breaks in the- 
moraines would probably be maintained by the escape of rivers fed from 
the melting ice. It is clear that the lower part of this valley, below 
Lemont, had for some time been occupied by a large and much over- 
loaded glacial river. While the ice lingered at the moraine, the vallev 
had been deeply aggraded with gravels, to the altitude of about (>‘>() 
feet above sea level, at Lemont ( Lm. in Fig. 10). The terraced remnants 
of this old valley train at certain places between Lemont and Joliet 
have just been described. While the valley train may have had its 
head near Lemont, in a sag in the main ridge of the Valparaiso mor- 
aine, it more probably extended eastward to the vicinity of Alt. Forest, 
where, during the last stand of the ice against the moraine, the escaping" 


GOLDTHWAIJ] 


HISTORY OF THE LOWER DES PLAINES. 


53 




Fig. 11. Two stages of the glacial lakes Chicago and Maumee. (Leverett and 
Taylor.) The first might represent conditions in the Glenwood stage; the second 
in the Calumet stage. Notice the expansion of the lakes northward as the border 
of the ice receded, and the shifting of the outlet of Lake Maumee from Fort 
Wayne to the Grand river, as the lower pass was uncovered by the ice. 


54 


THE DES PLAINES VALLEY. 


[BULL. NO. 11 


water's would be likely to maintain a flat-tioored valley.. With the de- 
velopment of Lake Chicago at the head of this valley, the character 
of the river was completely changed. The over-abundant supply of 
waste from the melting ice was now carried into the lake and left there. 
The river was thus relieved of its load, while suffering no diminution of 
volume, so it at once began to gather up the gravels it had previously 
laid down and thus to re-excavate the valley. 

While Lake Chicago was extending itself northward, as the edge of 
the ice retreated (Tig 11) its outlet was cutting a wide trench in the 
valley train, and so slowly lowering the level of the lake. (This is shown 
in profile, in Tig. 12). Along the shore of the lake at this time waves 
and currents were busily cutting terraces and building beaches like those 
of the present shore, at a height which indicates that the water stood 
about fifty-five feet above the present Lake Michigan. The common 
occurrence of a set of parallel beaches whose crest altitudes range from 
55 down to 50 feet above the present lake doubtless shows that the lake 
level was not exactly stationary, but was falling slowly as the out- 
flowing river deepened its channel. This earliest and highest stage 
of Lake Chicago has been named the “Glenwood” stage, because its 
shoreline is very conspicuous near Glenwood, Illinois. 

Calumet stage — The Lo deport sill . — We may get further light on the 
history of the outlet from the lower beaches of this extinct lake. About 
twenty feet lower than the Glenwood shoreline, in the Chicago district, 
is a strongly developed beach called the “Calumet” shoreline. It marks 
a stage when the lake stood for a considerable time at the height of 
30 or 35 feet above its present level. Lelow the Calumet beach is a group 
of shorelines, called the Toleston shorelines (from the town of Toleston, 
Indiana.) This includes a well defined beach, 20-25 feet above Lake 
Michigan, and a series of closely set ridges from 16 feet above the lake 
down to its level, which represents stages when the lake was falling from 
the Toleston level to that of the present Lake Michigan. Evidently the 
surface of Lake Chicago was not lowered steadily and uniformly from 
the 55-foot mark to the level of Lake Michigan, but went on inter- 
ruptedly, halting for a considerable time at the 35-foot level, then 
falling rather suddenly to 20 feet, and then by several successive lower- 
ings gaining its present level. 

Reasons for these spasmodic changes in level seem to exist in the 
way the Chicago outlet was deepened. As the river cut down farther and 
farther through the gravels, it seems to have encountered a ledge of 
bed rock at Lockport, (Tig. 12, a b c ) , at a height of hardly 30 feet 
above Lake Michigan. Downward cutting of the valley floor was at once 
arrested, while the surface of the rock was widely stripped of its cover- 
ing of drift and gravels. What seem to be remnants of this old rock 
floor or sill, which was formerly continuous across the valley, are flat 
topped terraces of rock in the village of Lockport and at a corresponding 
height on the west side of the valley near the Sprague school house. The 
surface of the rock terrace at Lockport is 30 feet above Lake Michigan. 
While the lake stood at the 35-foot level, therefore, the depth of the 


GOLDTHW AIT.J 


HISTORY OF THE LOWER DES PIAINES. 




ancient river, close to its left bank, at Lockport, was not more than fivt: 
feet. It seems probable that the surface of the rock sill (if one existed 
there) was lower than this near the center of the valley, and the river 
deeper than five feet there. On the basis of this supposed sill it is not 
hard to explain the manner in which it was worn through so as to cause 
a sudden drop in level of Lake Chicago. It would be natural for rapids 
to be established on the down-valley side of the sill, (at a in Fig. 12) 
perhaps near the head of Joliet pool, where the river passed from the 
hard Niagara limestone to the softer limestones and shales of the Cin- 
cinnati formation. Meanwhile on the up-valley side of the sill at 
Lockport, the river would be unable to cut its drift floor below the 
30-foot level, and the lake would consequently be held at a level a few 
feet above the channel floor, or about 35 feet, while the rapids on the 
iower side of the sill would he wearing backward past Joliet (towards 
b and c in Fig. 12.) Had the Niagara limestone been less massive 
and uniform in structure, falls instead of rapids might have been de- 
veloped, leaving, by their recession, a sharply defined gorge like that 
below Niagara Falls; but the structure of the rock at Joliet and Lock- 
port probably did not permit this. Where the rapids were swift, a 


b 

<r 

o 

a 


y 

7 

O 

£ 



Fig. 12. Diagram showing how the removal of a sill of bed rock in the Chicago 
outlet, by “stoping,” may have caused the sudden drop in level of the lake from 
the Calumet to the Toleston. 


steep, straight bluff of rock was left facing the valley. This seems to 
have been the origin of the high bluff on the west side of the river at 
Joliet, between Exchange street and TheileFs park, and on the east side 
at Lockport, from Dellwood park to the north end of the village. For 
the greater part of the course, however, no striking gorge was pro- 
duced. As the rapids receded up the valley towards Lockport, the 
distance across the sill became shorter and shorter. A sudden change’ 
followed when the rapids arrived at the very head of the sill (c in Fig.. 
12) and the last of the controlling ledge was removed. The drift 
boor above Lockport was degraded at once some 15 feet, down to the- 
lower rock floor, and the surface of Lake Chicago fell correspondingly 
to the “Toleston” level. While the removal of the barrier and the- 
fall of the lake should of course not be thought of as instantaneous, it 
would be sudden compared to the long time it would take for the 
rapids to eat back through the sill (from a to c ) a distance of perhaps 
four or five times. It might well have caused the lake to drop so 
promptly from the level 35 feet above the present lake to a level 20 
feet above it that no beaches wure built between the Calumet and the 
Toleston. 

Toleston and later stages — Abandonment of the outlet , and substi- 
tution of the Des Plaines river . — In the course of time the border of 



56 


THE J>ES PLAINES VALLEY. 


BULL NO. 11 ] 


tin ice withdrew northward past the low region at the head of Little 
Traverse bay and past the Straits of Mackinaw, and Lake Chicago 
merged with a larger lake. Lake Algonquin, which then occupied the 
Huron basin. Although the history of this lake lias not been fullv 
worked out, it seems probable that at the time the waters of the Mich- 
igan basin became a part of it. Lake Algonquin stood at a very low 
level, discharging eastward through the vallev of the Trout river near 
Kirkfield, Ontario. That region then stood much lower than now, and 
the surface of Lake Algonquin at that stage was probably considerably 
below the present level of Lake Huron and Lake Michigan. This low 
water stage was only a short one, however, for the northern part of the 
Croat Lake region, including the 'brent outlet, was soon raised, until 
the discharge of Lake Algonquin had been shifted to the St. Clair 
river at Tort Huron. This brought the surface of the waters in the 
Lake Michigan basin up to about 1*2 feet above the present level. The 
.series of changes which beset Lake Algonquin after this, as the ice re- 
ceded and as earth movements warped the northern part of the sur- 
rounding region, are complex, ♦and have not yet been fully worked out. 
It is enough here- to remark that the waters in rhe Michigm 
basin remained long at the 12-foot level, returning to it after a second 
.stage of low water that was probably even lower than the first had been. 
This was brought about by the uncovering of the “Xipissing v pass, 
east of Xorth Kav. Ontario, which at that time stood very close to sea 
level, and by the subsequent uplift of that region and re-establishment 
of the outlet at Tort Huron. At some time during these recurrent 
12-foot stages of Lake Algonquin and the Xipissing great lakes, the 
shallow Chicago outlet was shut off bv a long reef of sand which can 
be traced through the Chicago district from Lincoln park to South 
Englewood. The discharge of Lake Algonquin and of its successors, 
the Xipissing great lakes, came in this way to he concentrated at Tort 
Huron, where the outflow was across glacial drift instead of across 
hard rock. 

Thus the Chicago outlet was abandoned. In place of the great river 
whose volume was perhaps comparable to that of the St. Clair river 
today, was left the little I)es Plaines, a stranger in the district, which 
straggled into the great valley as if by accident. Extending its mouth 
out on the flat plain south of Riverside as the lake fell and its shore 
moved eastward, the Des Plaines seems almost to have had a free choice 
between a course to the Mississippi or to the St. Lawrence. During 
floods, if not at ordinary stages, the riveiyused to discharge a part of 
its volume eastward to the south branch of the Chicago river. The 
slough, “Mud lake." (See Fig. 19), which marks the old channel, may 
for a time have carried the entire river out towards Lake Michigan. 
What caused the channel to silt up and the river to turn westward near 
Summit is not known. Perhaps, as Mr. L. E. Cooley, consulting en- 
gineer of the Internal Improvement Commission, has suggested, a small 
colony of industrious beavers, building a beaver-dam, were responsible. 
Whatever the reason, the Des Plaines finally found its way westward ; 
and as a result the vallev of the extinct outlet has not been left wholly 


<i O LDTH WAIT.J 


HISTORY OF THE LOWER DES PLAINES. 


r- r-r 

O i 


unoccupied by drainage, but serves as a valley for a river several 
sizes too small for it. At Romeo, large pot-holes in the rock floor of 
the valley near the Des Plaines river tell tbe story of the deeper and 
more powerful river of ancient times. 

The amount of erosion that the Des Plaines lias accomplished in its 
straggling course on the valley floor is very slight. Even between 
Romeo and Joliet, where the steeper grade of the rock floor produces 
rapids in the river, its channel is low and ill-defined. Expanding and 
contracting as it enters and leaves shallow hollows on the outlet of the 
floor, branching and uniting about low islands which are not bars of its 
own construction, turning to right and left in its course down the 
valley, yet at no place (above Joliet) approaching near enough to under- 
cut the bluffs as they must once have been undercut, and occupying 
usually less than one-tenth of the width of the valley, the Des Plaines 
is manifestly an incompetent river. The valley it follows is not its own, 
but one which it inherited. 


EROSION BY TRIBUTARIES. 

Fraction run . — It is interesting to see what the tributary streams were 
accomplishing while the great outlet was being excavated. As an ex- 
ample of tributaries which enter the outlet midway of the supposed rock 
sill, we may take Fraction run, which joins the Des Plaines between 
Lockport and Joliet. Like the main valley, this tributary was ag- 
graded with gravels while the ice lay against the Valparaiso moraine. 
Remnants of a smooth-topped valley train remain in terraces on either 
side of Fraction run, in and above Dell wood park. The Chautauqua 
building stands on this terrace. Beyond the park fence, a short dis- 
tance up-stream, broader and better remnants of the outwash terrace, 
with gravelly constitution, are to be seen on both sides of the run, at 
a height of 15 feet above the present valley floor. 

During the Glen wood stage of Lake Chicago, while the ancestral 
river lowered its channel in the gravels down to the surface of the 
rock sill, its little tributary did the same. Fragments of the outwash 
were left as terraces standing above the rock floor of the run. While 
the rapids on the down-valley side of the Lockport sill were receding 
northward from Joliet towards Fraction run, the small side stream was 
adjusted to the level of the sill at its mouth ; but as the rapids migrated 
up the main valley past, the mouth of the tributary the side stream 
suddenly found itself tumbling over the face of a gorge, the perpen- 
dicular wall of rock which overlooks the old canal near the entrance to 
Dellwood park. The diagram, Fig 13, illustrates this process. The 
waterfall thus given to Fraction run must soon have been reduced to 
a series of rapids, for limestone of so uniform a structure, would not 
permit falls to be long maintained. By the recession of the rapids up 
the run, a steep-walled gorge was cut in the rock. At its mouth the 
gorge is equal in depth to the cliff cut by the main river in the sill, 
but toward the head of the gorge its depth decreases. Where so coarse 
a load is gathered and must be carried by the stream, it is forced to 


58 


THE DES PLAINES VALLEY. 


[BULL. NO. 11 


maintain a steeper slope than that of the old bed rock surface. In 
the park the bed of the stream has been obscured by the construction 
of two dams to form artificial ponds. Near the high cement bridge 
the gorge is cut about 20 feet deep in rock. The limestone there is thin- 
bedded, cherty, and very much cracked by joint planes. Just above the 
bridge, near the upper dam and the trestle of the scenic railway, is a 
fine natural exposure of the limestone, coated with lichens. The over- 
hanging cliff is due to a slightly inclined joint crack. The strata dip 
10° to 15° toward the southwest, with local warpings. One may see 



Fig. 13. Diagram illustrating the way in which the up-river valley migration 
of falls or rapids on a river affects its tributaries. The falls have been worn back 
from near the front of the diagram past tributaries a and b, and are now ap- 
proaching c. When they pass c, the mouth of the side stream will be suddenly 
lowered from the level of the crest of the falls to that of the base, forming a fall 
or rapids there. This has just occurred at b. These falls or rapids will then re- 
cede up the side valley, forming a branch gorge. This stage in the process has 
just been reached at b, but has been passed at a. 

here the way in which the much jointed rock on the cliff face is wedged 
and loosened by frost and deca}g falling, piece by piece, into the stream. 
Should the process seem too slow to account for the sculpturing of the 
gorge, we must remember that the age of the gorge is to be measured, 
not in tens, but in thousands of years. 

Farther up the run, beyond the park fence, one may see in its natural 
condition the rocky channel of the stream at the shallow head of its 
gorge. A long string of riffles and pools formed by the step-like bedding 
planes illustrates remarkably well, though on a small scale, the un- 
graded condition of a young stream. Here also is a precipitous 60-foot 


goldthwait] . HISTORY OF THE LOWER DES PLAINES. 59 

bluff, where the run has swung against the north side of its valley, de- 
stroying the outwash terrace and trimming back the moraine and the 
underlying rock (See Plate 5, B.) The valley floor above the park is 
broad and flat, built of loose rubble which the stream has torn from its 
banks. It appear to have been the flood plain of the creek when it was 
adjusted to the level of the rock sill, and to have been only slightly 
trenched by the channel since the development and headward extension 
of the rapids up the run. Opposite the high bluff, on the south side 
of the valley, a broad fiat remnant of the outwash terrace, 15 feet above 
the present valley floor, runs from the northeast corner of the park up- 
stream several hundred yards, and there finds continuation in a broader 
terrace on the north side of the vallev. 

Long run and other tributaries above the sill . — Two sets of terraces 
occur along the run. The higher is an outwash or valley-train terrace, 
to be correlated with the Glenwood stage of Lake Chicago, and the 
lower one is a terrace adjusted to the rock sill at Lockport, contem- 
poraneous with the Calumet stage of the lake. Where Long run enters 
the main .valley, a mile south of Romeo, the two terraces alluded to 
may be seen from the trolley car. The outwash terrace is about 30 
and the lower terrace, 12 feet above the creek. 

Other tributary ravines which enter the upper portion of the outlet 
between Willow Springs and Lemont, sometimes show two terraces. 
One of these is a large ravine a mile and a half east of Lemont (in 
sections 22 and 27, Lemont township). The two terraces appear near 
the mouth of the ravine, in plain sight of the road that runs south 
from the school house. The higher stands about 30 feet above the 
present flood plain and the lower 15 feet above it. Only a few remnants 
of the higher one remain, but the lower one may be followed inter- 
ruptedly far up the valley, where the present flood plain gradually 
rises to meet it. Judging from the interval between the old flood plain 
remnants and the present floor of the ravine, near the main outlet, the 
higher terrace corresponds with the Glenwood and the lower with the 
Calumet stage. 

Ravines cut by streams which entered Lake Chicago along the north 
shore at Glencoe, Waukegan, and Zion City, show terraces at the same 
height as the ravines which entered the outlet above Lockport. They 
obviously mark repeated lowerings of the lake, which correspond with 
repeated deepenings of the river. 1 

Spring creek and Hickory creek. — Both Spring creek and Hickory 
creek were aggraded with valley trains, like Long run; and since they 
are larger streams they have even more conspicuous outwash terraces 
than it has. The lower terrace seems to be absent here, however, this 
suggests that these creeks may have joined the main river below the 
Lockport sill, so did not have to adjust their floors to a temporary 
rock barrier. 


l For a description of these ravines, and a discussion of their significance, see 
Bull. 7 of the 111. Geol. Surv., on the “Physiography of the Evanston-Waukegan 
District,” by W. W. Atwood and J. W. Goldthwait, pp. 69-84. 1908. 


THE DES PLAINES VALLEY. 


[BULL. NO. 11 


GO 


Sugar creek . — Unlike the otlier tributaries near Joliet, Sugar creek 
has had to cut down its channel in bed rock; for the Niagara limestone 
there rises higher than on Hickory creek. 

Accordingly, it has worn out a narrow gorge in the flat-bedded lime- 
stone from the Chicago & Alton railway bridge down to the slaughter 
house road, near the old tin-plate mill (See the map of this gorge, 
Plate 6.) The gorge is nearly 15 feet deep, with vertical cliffs cut out 
along joint cracks and a rock floor broken by a long succession of little 
rapids, where the edges of the harder, chertv beds offer greater resistance 
to erosion. These little water-falls (for such they are, except when 
the stream is flooded) frequently cross the gorge ; not in a straight 
line, but in a curve, which is concave down stream on account of the 
more rapid recession in the middle, where the current is faster than 
at the sides. In this regard they imitate the great Horeshoe falls of 
N iagara, which, as it happens, plunge over the very same limestone form- 
ation. In the pools between the rapids, one may see in low water the 
chipstone waste that is being swept down stream during each flood. 
The discoidal or tabular blocks and pebbles (even the larger slabs which 
have been banked up bv the boys to form a swimming pool, and then 
moved by the creek, in floods) lie packed like the overlapping shingles 
on a roof, slanting up stream. The shingle structure is even more im- 
pressively shown on Hickory creek, below the old red mill, where the 
freshet of February, 1907, scattered large tabular slabs and chips of 
rock far and wide over the flood-plain. 

The jointed walls of the gorge of Sugar creek offer favorable op- 
portunity to study the manner in which joints aid or direct stream 
erosion along definite lines. The bare walls, faced by joints, permit no 
doubt as to the advantage taken bv the stream to tear away the limestone, 
block by block, as the workman does in quarrying. At the same time, 
it is clear from the course of the creek, which runs oblique to the two 
master systems of joints in such a way that the walls of the gorge have 
a zigzag, rather than a straight course, that while joints aid the stream 
thev mav not direct its work along definite lines. Instead of running 
parallel to either of the two prominent sets of joints, the gorge of Sugar 
creek bisects the angle between them. On the map, where the direc- 
tion of the joints near the gorge is shown by a symbol, the discordance 
between the joints and the trend of the stream comes out plainly. 

Reed’s ivoods ravine . — One of the prettiest and most instructive ex- 
amples of excavation by a tributary in the glacial drift is the ravine 
in Feed’s woods, above Bush park (See Plate 7). There are several 
features to be observed here which, taken together, cannot fail to con- 
vince one that this deep ravine and its tributaries have been carved out 
wholly. by the activitv of rain and running water. 

In the first place, the behavior of the creek and its little tributaries 
during wet weather is significant. The main channel at such times may 
be filled brim full or even to overflowing, so that the little flood-plain 
which forms the floor of the valley is under water. In its swollen con- 
dition the stream may be seen to carry fine sediment in suspension and 
to roll sand and fine gravel along the bed of the channel. Around the 



Tfl 

> 

H 

H 


OS 


GEOLOGICAL SURVEY. BULL. NO. 11, PL. 








GOLDTH WAIT.] 


HISTORY OF THE LOWER DES PLAINES. 


HI 


outside of every sharp curve — and there are many such — the stream 
has cut away its bank. At points where the channel swings against 
one side of the valley, bare slopes of glacial drift may be seen, several 
feet high and very steep. After a rain it is not unusual to find little 
pillars of clay, capped by pebbles or other protective objects, around 
which the rain has excavated the fine clay. Obviously, with the wash- 
ing away of soil from exposed side slopes and from the channel bank 
the ravine is changing form, be it ever so slowly. 

Material thus obtained is washed into the stream and swept down- 
valley (except such large pebbles and bowlders as cannot be moved), 
to be deposited sooner or later in the channel on the inside of some 
curve, often directly opposite a place where cutting of the outer bank 
is going on. It is by this “cut-and-fiH" process that the Hood-plain has 
been built, for even now it is being broadened by the extension of de- 
posits on the one side and by lateral erosion on the other, at those points 
where the channel swings to the extreme border of the floor. In the 
freshly exposed channel in dry weather may be seen the stratified struc- 
ture of the flood-plain, due to its having been built up under water by 
sediment transported by the stream. Each variation in volume of the 
stream means a variation in its carrying power; hence it is repeatedly 
depositing a layer of different texture from the preceding layers. The 
surface of the flood-plain is, indeed, merely a part of the waste material 
that is gathered up bv the creek and its wet weather branches and is 
just now on its way down to the valley of the Des Plaines.' Not only 
will the stream gather sediment from either side, hut it will pick up 
material from the bed of its channel d iring each flood, and the channel 
floor will be lowered thereby. Judging from the rate at which the 
waste is moving down the fllood-plai 11-path — a slow rate, to be sure, oper- 
ative only in wet weather, yet a perceptible one — we may believe that in 
the thousands or tens of thousands of years during which the drift has 
been exposed to running water, a ravine as large as this has been exca- 
vated. The process of transportation must needs involve excavation. The 
ravine, then, is constantly growing deeper as the stream cuts downward 
along its bed, and wider as the stream planes away the border of its 
flood-plain, and rain washes down the side slopes. 

In this connection it is worth while to consider the effect which exca- 
vation has at the head of a ravine. Examine, for instance, the ex- 
treme upper end of some little side ravine or gully (selecting, of course, 
one in which the natural conditions have not been upset by artificial 
drains or rubbish heaps.) The one in Plate 8 , A, for instance, is a 
straight, steep-sided gully, usually without sod, exhibiting the sharp 
outlines of a recently rain-cut surface. When it rains, the water which 
falls in this gully and that which is shed into it cuts down its steeply 
inclined bed and thereby cuts back its head. The deepening and the 
headward growth of such a gully are inseparable. Thus, while the water 
is running from the head toward the mouth of a stream, the stream 
valley and, consequently, the stream itself, wear headward, or, as it 
might seem, backward. The exact direction in which the gully works 
back is determined partly by inequalities of surface slope — for a de- 


THE DES PLAINES VALLEY. 


[BULL. NO. 11 


62 

pression which concentrates the run-off and delivers it to the gully will 
cause the g'ullv to lengthen in that direction; and partly by inequalities 
in structure of the ground, for if hard and soft materials lie side by 
side, the running water will select a path along the soft belt. Even 
foreign obstruction like tree roots or large bowlders serve to turn a 
young valley to one side, and perhaps wholly change its future course 
of growth. Here then, at the extreme head of a ravine, we may see 
the work of excavation in its infantile stages. The difference between 
the head-water gully and the full grown main ravine, is one not of kind, 
but of size. This stream has only recently worked back to the gully 
head, and there its volume is exceedingly small; consequently very little 
excavation has been accomplished. The main ravine, however, began 
long ago to be cut out by the growing stream, and with its growth the 
size and power of the stream has been increased at a more and more 
rapid rate. 

Another feature that demands attention is the straightness of the 
young gully. It is a matter of easy observation that an enlarged gully 



Fig. 14. A crooked gully in an early stage of development. 

or small ravine like the one which enters Rush creek from the north 
in the center of Reed's woods (See Plate 7), follows a crooked path 
on its way down to the main ravine, bending back and forth between 
a series of projecting spurs. Where developed under favorable con- 
ditions, these bends may be exceedingly symmetrical and evenly spaced. 
Careful inspection and legitimate reasoning show that they represent 
irregularities or crooks in the incipient gully which have been enlarged 
and modified until they approach conventional curves as small acci- 
dental obstructions become less and less effective and the minor crooks 


Map of the Ravine in Reed’s Woods 



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STATE GEOLOGICAL SURVEY. BULL. NO. 11. PL. 



# 






GOLDTHWAIT.j 


HISTORY OF THE LOWER DES PLAINES. 



are eliminated (See Figures 14 and 15.) While the curves which survive 
in this growth are slowly enlarged by outward cutting, they begin to 
shift distinctly down-valley. The explanation of this lies in the fact 
that wherever a stream winds around a spur it cuts a little more strongly 
against the up-valley side of that spur than on the down-valley side of 
the spur next above. Thus, while the stream curves push their way 
slowly down-valley, and the spurs are slowly consumed by the trimming 
away of their up-valley sides, the valley itself is widened, and soon the 
beginnings of a flood-plain may be seen. The main ravine (that of 
Bush creek on the map, Plate 7) has passed through exactly these 
stages of growth. It has not only been deepened 25 feet below the 
upland level, but by the lateral swinging of the creek it has been 
widened about 150 feet. At the same time, by the down-vallev shifting 
of its curves, the original spurs have been half trimmed away. The map 



Fig. 15. Same gully as in Fig. 14, in a later stage: As the gully has been 

deepened by the growing stream, the crooks and bends have become larger and 
more conventional. A series of overlapping spurs has been formed. On the outside 
of each curve and the up-valley side of each spur the stream is actively trimming 
its bank. On the inside of each .curve and the down-valley side of each spur it is 
building a flood plain. 

shows plainly the manner in which the creek is attacking the up- 
valley side of three half-consumed spurs in Reed’s woods. Obviously 
this is not an accidental but a systematic relation. At these points 
the steep bank of the ravine is bare where the stream has recently been 
undermining it. Perhaps a tree leaning over the creek at a precarious 
angle tells the same story of the continued activity. What better ex- 
planation for these phenomena than that the ravine is being and has 
been cut out by the creek ? How else, indeed, can such a group of facts 
be accounted for? If there should still be doubt regarding the ability 
of so small a creek to excavate so large a ravine, we must consider the 


THE DES PLAINES VALLEY. 


[BULL. NO. 11 


Hi 


statement of an old-time Scotch geologist, John Playfair, who. calling 
attention to the manner in which side valleys of a river system join 
the main valley, declared, in 1802, that side valleys have “such a .nice 
adjustment of their declivities that none of them join the principal 
vallev either on two high or too low a level; a circumstance which would 
be infinitely improbable if each of these vallies were not the work of the 
stream that flows in it." 1 2 

This feature, as well as the others, is illustrated in the Bush creek 
ravine. They are not “ready made” valleys; fashioned for the streams; 
thev have been slowly and laboriously cut out bv the streams themselves, 
and testify to the changes which can he wrought out in long periods 
of time. This creek, it might he remarked, is probably some thousmds 
or tens of thousands of years old. - 

Before leaving this ravine a few minor points should not be oxer- 
looked. The process of downward excavation seems to have been ar- 
rested at least once; for there are fragments of the old valley floor now 
in the form of terraces, on the down-valley side of spurs, at a height of 
about eight feet above the present flood-plain. Whether this terrace 
corresponds to the stage when -the Des Plaines valley was aggraded with 
the valley train or to some subsequent stage of temporary interruption 
of the process of excavation cannot confidently be told. The amount 
of work accomplished by the creek in cutting down to the level of the 
terrace seems to indicate a later stage than that of the outwash filling. 
If so, either the Loekport sill extended down-valley as far as the mouth 
of the creek, or there was some other obstruction in the valley to hold 
the tributary for a time near a local base level. The presence of ter- 
races at various levels around the base of Flathead mound, a few miles 
farther down The Des Plaines valley, suggests that even down beyond 
the Loekport sill the old outlet of Lake Chicago rod iced its channel 
bv successive stages. Another small feature of the basin in the Bush 
creek ravine is an outcrop of cemented gravel, or conglomerate, in the 
bed of the creek, where it is cutting against a long spur (“Cg. v on map). 
Probably this conglomerate underlies the glacial drift all about here, 
as it does in the northeast part of Joliet and elsewhere. 


ALLUVIAL FANS AND CONES. 

Since the outlet of Lake Chicago stopped flowing and its 
valley floor is all but abandoned, the excess of detritus brought 
down by the tributary streams has in many places built up 
distinct fans and cones. One of these, near Joliet, a broad, fiattish Ian 
of sand, may be seen at the mouth of a small ravine which issued from 
the high bluff, half a 'mile northeast of the penitentiary. Were the old 
outlet restored, it would collect all this waste and carry it down the 
vallev: but without a full sized river to receive and transport the ma- 


1 “Illustrations of the Huttonian theory of the earth.” p. 102, 1802. 

2 The post-glacial interval during which the surface of the “Wisconsin drift 
has ben exposed to stream development seems to be somewhere between 20.000 and 
60.000 years long. (Chamberlin and Salisbury’s “Geology,” Vol. Ill, p. 120 .) 
This portion of Illinois was uncovered by the ice sheet soon after it began to re- 
treat, for the terminal moraine of the last great ice advance lies only a few miles 
west of Joliet. Hence the drift surface here may have been uncovered 50,000, or 
at least nearly 20,000 years ago. 


goldthwait . ] HISTORY OF THE LOWER DES PLAINES. 


65 


terial, the tributary, when swollen by floods, is forced to drop its load 
where it debouches on the flat valley floor; and in so doing it is choked 
and split into innumerable distributaries, after the fashion of fan- 
building streams. If we knew just how much sediment was being 
brought down by this little tributary each year (probably almost wholly 
during severe floods, and knew the total volume of the fan, we might 
obtain from it a rough measure of the number of years since the outlet 
stopped running — rough, because the rate of growth of the fan has 
probably varied much from time to time. 

A group of three well marked cones may be seen along the base of 
the steep 80 -foot bluff beside the trolley road half a mile southwest of 
Willow Springs. They rise with moderately steep slopes thirty feet 
above the road, where each has its apex in a steep, narrow ravine. The 
longest of the cones is some fifteen rods from apex to base. 

These cones and fans exemplify on a small scale the alluvial de- 
posits which border the great valley of California, where, with a rich 
soil and ideal facilities for irrigation, the fans have been transformed 
into great fruit orchards. 


66 


THE DEK PLAINES VALLEY. 


[BULL. NO. 11 




CHAPTER VI. 


PHYSIOGRAPHIC HISTORY OF THE UPPER DES PLAINES 

RIVER. 


DEPOSITION OF THE TILL RIDGES. 

In the preceding chapter it has been explained how the great U- 
shaped belt of upland which encircles the south end of Lake Mich- 
igan- — the Valparaiso moraine — was built up under the edge of a tongue 
of ice which occupied the lake basin. So long as the melting of the 
ice, at the border of this tongue or lobe, was only fast enough to balance 
the forward movement of the ice mass, the ice border was nearly 
stationary; and all the rock debris, or “drift/* that was carried forward 
to the edge of the glacier was banked up to form the moraine. At 
length the climate moderated somewhat, and melting came to exceed 
advance. The Lake Michigan ice lobe shrank back toward the center 
of the lake basin — not steadily, however, but spasmodically. Several 
times the ice front halted in its retreat, and each time it built beneath 
its edge a broad ridge of till, lower and smoother than the Valparaiso 
moraine but like it in origin. Thus there grew up in Cook and Lake . 
counties three successive till ridges of the “lake-border morainic sys- 
tem/* between the Valparaiso moraine and Lake Michigan. Between 
them were lowlands of exceedinolv faint relief. 

O 

In Racine and Kenosha counties (Wisconsin) the lake border ridges 
are five in number, but passing southward into Illinois they merge to 
form three (See Fig. 1.) They do not continue around the south end 
of the lake, but terminate in Cook county, as shown on the map ; the 
inner, or east ridge, at Winnetka; the outer, or west ridge, north of 
Oak park. In Indiana and Michigan, however, they reappear inside 
the Valparaiso moraine. The outermost of the lowland belts between 
the west ridge and the Valparaiso moraine forms the basin of the 
Des Plaines river, above Oak Park. There the ending of the west 
ridge allows the Des Plaines till plain to open upon the broad Chicago 
plain. 

In detail of relief, these border ridges are very weak. Instead of 
the marked knob-and-kettle topography of typical terminal moraine, 
their surfaces present low, undulating swells and sags, faint knolls and 
shallow sloughs. Only when followed for a long distance or plotted on 


GOLDTHWAIT. ] 


HISTORY OF THE UPPER DES PLAINES. 


67 


a map is the ridgelike character appreciated, so gentle are the lateral 
slopes. At Park Ridge, for instance, the outer* moraine is about two 
miles broad, and its crest only twenty-five feet higher than the till-plain 
of the Des Plaines valley. The west slopes of the till ridges are some- 
what more pronounced than the east ones. As the ice border receded 
and these till ridges, with their intervening lowlands, appeared, a new 
drainage system began to develop. At first, doubtless, the streams which 
flowed through the depressions were burdened by outwash from the 
ice, and started to form alluvial plains or valley trains like those of 
the lower Des Plaines valley, described in Chapter V, And Figs. 8 and 9. 
The depression between the east and middle belts of the Valparaiso 
moraine, now followed by Salt creek, above Fullersburg, and by Flag 
creek below, was doubtless occupied thus early by streams. Probably 
the singular bend of Salt creek at Fullersburg (See Fig. 10) was gained 
at this time, through an initial depression which ran transverse to the 
east ridge and had been an avenue of glacial discharge like the sag in 
the west ridge north of Joliet (See Fig. 8), or like those above Lemont, 
though less marked. 

The right-angled turn at Fullersburg, by which Salt creek leaves , 
the inter-morainic depression close to the head of Flag creek has drawn * 
the attention of writers on the geolog}^ of the district, at various times. 
The relation of the two streams resembles that which frequently re- 
sults from “river piracy,” the capture of the upper portion of a stream 
by the headward extension of a more rapidly growing and more deeply 
entrenched neighboring stream. The more rapid growth of the “pirate” 
is usually attributed to advantage from a shorter, steeper course, or of 
a weaker rock structure to encounter, or of a larger volume (perhaps 
because of heavier rainfall.) In the present case, it might seem that the 
upper part of an ancestral “Flat creek,” 'which followed the lowland 
southward past Fullersburg, was captured by the headward growth 
of a transverse stream which had begun its growth on the east, slope of 
the moraine, (i. e., the present lower course of Salt creek). The upper 
part of this ancient Flag creek, above Fullersburg, would thus become 
a part of Salt Creek, and would be diverted into the Des Plaines at 
Riverside, while the lower part of it would be left in a beheaded con- 
dition, the Flag creek of today. FTo positive evidence, however, of river 
capture at this place has been found; nor does there seem to have been 
any reason for piracy. Salt creek, below Fullersburg, seems to have 
had no advantage over Flag creek, either as to the length of its course 
or as to the structure it encountered. So the rather singular escape of 
Salt creek from the broad valley seems to be best explained merely 
as one of the freaks of glacier-made drainage, inspired by an irregu- 
larity of the newly exposed surface of drift. 

LAKE CHICAGO. 

GLENWOOD STAGE. 

While the ice sheet was withdrawing from the Valparaiso moraine 
to its next position, waters gathering along its border in the Chicago 


68 


THE DES PLAINES VALLEY. 


[BULL. NO. II 


district began to assume the outline of a crescentic lake, glacial Lake 
Chicago (Fig. 11.) The overflow of this lake escaped across the Val- 
paraiso moraine along the line of the lower Des Plaines valley. 



Fig. 16. Part of Lake Chicago during the Glenwood stage (copied, with some 
modification, from Alden). Outline of Des Plaines bay inferred from the 50-foot 
contour on the map of the Sanitary district. Hachures show wave-cut and river- 
cut bluffs ; dots show beaches and spits. 

A long shallow arm of the lake, two or three miles wide, reached 
northward from Oak Park up the depression between the west ridge and 
the Valparaiso moraine to the vicinity of Franklin park (Fig. 16). 
Further north the inter-morainic depression was probably a long slough. 


/ 


<GOLDTHWAIT.] 


HISTORY OF THE UPPER DES PLAINES. 


69 


on which the upper Des Plaines, fed largely by the melting of the ice 
to the north, and subject to overloading with waste, followed an ill- 
defined, “braided” course. As the ice border melted back, leaving this 
long bay or slough, outwash gravels accumulated on its floor to a depth 
of several feet. These deposits of stratified gravel are from 10 to 12 
feet' thick near the village of Des Plaines. A thin overlying sheet of 
brown sand, used as moulding sand at the iron foundry, may record the 
change from the overloaded, glacier-fed stream to the normal stream of 
diminished volume and load, which followed the withdrawal of the ice 
from the vicinity. Although the shallowness of the bay prevented the 
development of recognizable shore topography, its boundary may be 
considered to follow the contour which is fifty feet above Lake Michigan, 
for that is about the altitude of Lake Chicago at its earliest stage, judg- 
ing from the altitude of well defined beaches in the Chicago district. 

The largest stream tributary to the bay at this highest, or “Glenwood” 
stage was doubtless the upper Des Plaines, which seems to have entered 
it not far above Franklin park. The smaller creeks which head west of 
the valley on the Valparaiso moraine and are now tributary to the 
main river between Des Plaines village and Maywood could have brought 
no significant amount of sediment into the bay, though their courses 
above the 50-foot level were no doubt already established. 

The Oak Park Spit . — Across the mouth of Des Plaines bay a long 
spit, or bar, was constructed by the waves and shore currents of the 
lake as they swept their supply of beach gravel and sand southward 
in the direction of the prevailing drift (See Figure 17). From the be- 
ginning of the spit, where it extends out from the end of the west till 
ridge north of Oak Park, to its termination near the Twelfth street 
bridge, the distance is about three and a half miles. As far south as 
the point where it crosses the Chicago and North-Western railway at 
Oak Park its form and height make it appear to have been a visible reef, 
rising above the lake during the Glenwood stage and separating the 
lake from the bay. Its southern half, however, is lower and flatter, 
and probably was submerged. Spits and bars like this one grow up only 
along irregular shores. They express a more or less successful attempt 
on the part of the waves and currents to replace the re-entrants of a 
shoreline with straight or gently curved beaches. In order to see how 
the Oak Park spit was constructed, we must understand the conditions 
under which beach material moves along" shore. 

Ordinarily during a storm the waves run ashore obliquely rather 
than straight on; for it does not often happen that the wind is blowing 
perpendicular to the shore. When the shore line is irregular, the 
chances for a straight on-shore wind at any place are still smaller. At 
most places the wind strikes the shore at an angle, and the waves run 
up more or less obliquely. So there comes about an along-shore trans- 
lation of water in the form of a definite current. The more oblique 
the wind and the greater its force, the swifter is this current. , Only 
during storms is the shore current sufficiently strong to transport sand 
and gravel as it is danced up and down by the breakers. 


70 


THE DES PLAINES VALLEY. 


[BULL. NO. 11 



Fig. 17. Map of the district about Oak Park and Maywood (from map of the 
Sanitary district). Contour interval, 5 feet above Chicago datum. Oak Park spit 
indicated by dotted pattern ; form of Des Plaines valley, by contours. 


GOLDTHWAIT. ] HISTORY OF THE UPPER DES PLAINES. <1 

% 

At a given place on the coast the shore current may he reversed from 
time to time as the storms bring waves from different quarters. As a 
rule, however, the wind from one direction is the dominant wind. It 
may almost invariably be the strongest, or it may last longer than any 
other storm wind, or it may have a greater “fetch” across the lake- or 
bay ; or these elements may be combined. In any case, the wind from 
one direction, usually sweeps so much stronger waves that it controls 
the movement of beach material along shore. On the southwest shore 
of Lake Michigan the dominant strong wind (i. e., storm-wind) comes 
from the north and northeast. Sweeping some 200 miles lengthwise 
of the lake, it developes stronger waves than the winds from other 
directions. It matters little that southeast storms are more frequent 
than “northeasters,” and the southeast winds fully as strong as those 
from the northeast. Our shores at the southwest corner of the lake 
are relatively sheltered from the south and exposed to the north; lienee, 
the dominant shore current along the Illinois border of the lake runs 
from north to south, and has done so ever since glacial Lake Chicago 
first took shape. - 

Waves and shore currents always act together. On shelving shores, 
where the waves in time of storm break in a long line some distance 
off-shore, the agitation of sand and gravel beneath the breakers offers 
a chance for the shore currents to- shift the particles along the line 
inch by inch. Relatively large pebbles, while thus raised in momentary 
suspension beneath a breaking wave, may be worked along by a current 
which would be too weak to move them unaided. The abundance of 
gravel in the Oak Park spit, with pebbles even two inches in diameter, 
ceases to be surprising when it is remembered that the drift of debris 
along a spit is accomplished by the combined forces of waves and currents. 

Supplementing the shore currents, the advance and retreat of the 
waves up and down the beach when the surf is running in obliquely 
causes a drift of beach material along shore at the water's edge. The 
wave dashes diagonally up the beach, sweeping sand and gravel with 
it; then receding the water pulls back some of the waste, either straight 
down the slope or still somewhat obliquely along the beach. Thus a 
pebble or grain of sand journeys along the shore in a zig-zag path, stop- 
ping from time to time, to be soon picked up by other waves and carried 
farther on. When an off-shore reef of sand has grown up to water-level, 
it will be built up farther into a barrier by material shifted along shore 
by the waves. 

So, during the Glenwood stage of Lake Chicago, the strong shore cur- 
rent which swept southward along the cliff border of the till ridge from 
Norwood Park past Dunning and Montclair, and out across the mouth of 
Des Plaines bay found its velocity somewhat checked by the increasing 
depth of water (its energy becoming diffused) and weakening, deposited 
its load of sand and gravel in spit-like form. Once started, the spit grew 
southward and westward by continued addition to its free end, much 
as a railway embankment is extended by a train of cars which carry 
gravel out to a dumping place at its extremity. ‘ Thus the accumulation 
not only rose above lake level, but grew in length. As the spit reached 


72 


THE DES PLAINES VALLEY. 


[BULL. NO. 11 


out into the bay it turned somewhat toward the west, following the bend 
which the shore current made in its delayed attempt to enter the re- 
entrant. The most pronounced part of the curve comes at Oak Park 
avenue and Ontario streets, where the spit bends rather sharply, crossing 
the grounds of Scoville Institute, and takes nearly westerly course along 
Lake street. This curving of the spit was not accomplished by a simple 
continuous growth along the line of deflected current. Several times 
the growing end of the spit was temporarily deflected as if by the waves 
of a series of unusually severe storms, which turned the shore current 
farther into the hay. Later, the normal direction of the shore current 
was restored, however, and the spit grew southward as before, the tem- 
porary hook being left behind the new outer beach ridge. The most dis- 
tinct hook of this sort lies just north of Lake street, between Kenil- 
worth avenue and Marion street. Another, nearly obliterated by street 
grading, may be traced from Euclid and Superior avenues westward to 
Elizabeth court; and a fragment of a third appears in the yards on the 
north side of Lathrop avenue west of Harlem avenue. This hooked ex- 
tension of the Oak Park spit seems formerly to have reached nearly a 
mile west, to River Forest ; but the extreme faintness of its slope, and the 
destructive grading of the railway and the streets have left little trace of 
it. The 50-foot contour on the carefully prepared map of the Sanitary 
District (Figure 17), however, as well as the 360-foot contour of the 
less detailed Riverside Sheet of the U. S. Geological Survey (where alti- 
tudes refer to sea level) indicate its trend. 

In the vacant block between Linden and Euclid avenues, Oak Park, 
and north of Superior, the spit has the form of a very pronounced ridge, 
and, like most of the old beaches, is clothed with a belt of oaks. Its 
crest rises more than 15 feet above the former lake floor to the south- 
east, and nearly 10 feet above the old bay floor to the northwest. The 
hack slope is somewhat steeper than the outer or lakeward side. Tfte 
gravelly condition is revealed in shallow cuts near the sidewalks. This 
north part of the Oak Park spit, with its characteristic beach profile, 
from its beginning at the south end of the till ridge (north of Division 
street and Ridgeland avenue) to the railroad station, probably rose above 
the water, separating the bay from the lake. 

South of the railroad the spit finds extension in a lower and much 
flatter ridge of gravels, which is followed by Des Plaines avenue for 
over a mile, or nearly to Twelfth street. This portion of the spit rises 
less than 10 feet above the lake floor, with faint slopes, and so seems very 
probable to have been a subaqueous reef along which beach material was 
drifting, but which never rose as high as lake level. It is composed very 
largely of fine gravel with pebbles less than 1 inch in diameter, as can 
be seen in the cuts beside the Great Western railway : but near the south 
end of the spit, in Waldheim cemetery, artificial pits near Twelfth street 
show an abundance of coarse gravel in which the pebbles are 2 inches in 
diameter. The strata here dip steeply toward the south, the direction 
in which the end of the spit was being extended. 

The reason for the southerly direction of this half of the Oak Park 
spit is somewhat in doubt. It has been explained as “probably due to 


GOLDTHWAIT.] HISTORY OF THE UPPER DES PLAINES. 73 

the combined action of the northeast winds and the current of outward 
flow from the estuary. The wind turned the spit westward until the 
outlet of the estuary was somewhat constricted, when the outward flow of 
water became sufficiently strong to deflect the spit-building current 
again southward.” 1 In a bay of such length and width, with a tributary 
stream, the Des Plaines, to maintain an outward flow of water, this ex- 
planation may fairly be questioned. It seems much more probable that 
wave action in the bay with wind from the north, producing a current on 
the bay side of the spit, would be competent to prevent its extension in 
a westerly direction, and, in conjunction with the dominant southwest- 
ward drift in the lake, would direct the spit southward. 

While the Oak Park spit did not wholly shut in the Des Plaines bay, 
its construction went far toward replacing the initial irregular shoreline 
with a gentle curve, such as characterized the more advanced stages of 
shore development. 

Shoreline between Maywood and Mt. Forest . — That part of the Glen- 
wood shoreline which lies west of the Des Plaines river is neither so 
characteristic nor so interesting as the portion near Oak Park. Across 
the mouth of the Des Plaines bay west of the end of the Oak Park spit, 
a hardly perceptible beach was built at the border of the shallow water 
south of Maywood. A small tract of land here, around Broadview, was 
probably a swampy island close to lake level. North of LaGrange, how- 
ever, the gentle east slope of the Valparaiso moraine is bordered by a 
rather sloping bank 15 to 20 feet high, which faces the lake floor. This 
•seems to have been a low lake cliff rising from the water’s edge like the 
bluffs along the present lake shore north of Evanston. The height of the 
lake floor at the base of the cliff is approximately 50 feet above Lake 
Michigan, the altitude of the extinct lake so far as can be judged from 
the best developed terraces and beaches. This cut bluff may be traced 
northward from La Grange more than two miles to Salt creek, where it 
fades away. Just east of the Butterfield road the crest of the bluff is 
crowned with a ridge of gravels for a distance of over a quarter of a 
mile. It is plainly seen in the cemetery and in the gravel pits a few 
rods north. Since the crest of the ridge stands 10 feet or more above 
the base of the bluff, it seems necessary to regard it as the beach of a 
somewhat earlier period, probably the very beginning of the Glenwood 
stage, when the lake stood for a while as high perhaps as 60 feet above 
Lake Michigan. This beach ridge controls the course of Salt creek for a 
considerable distance, as far north as Twenty-second street, where the 
creek turns and enters upon the lake floor. This northward deflection 
indicates that the direction of shore currents near La Grange, in the 
Glenwood stage, was towards the north. That is to be expected, because 
La Grange stands near the mouth of the old bay, where exposure to 
east and southeast winds was great, while exposure to the north was 
much reduced by the protection of the Oak Park spit. 

South of La Grange, as far as McCook, the same cut bluff may be fol- 
lowed; but it is not always plainly defined, for cultivation of fields 


l Alden, U. S. Geol. Surv., Chicago Folio No. 81, p. 8. 1907. 


74 


THE DES PLAINES VALLEY. 


[BULL. NO. 11 


seems to have greatly softened its outlines. Rounding the rocky hillside 
at McCook, it loses distinctness and passes along the uneven border of 
the moraine to the head of the outlet near Mt. Forest. 

Around the northeast end of Mt. Forest island, imperfect traces of a 
Glenwood bluff may be seen here and there. Near Archer road the ter- 
race at the base of the bluff is somewhat inclined, and stands a little 
lower than the Glenwood level. Further east, near Hartman avenue and 
Eigthty-seventh street, two distinct beach ridges mark the Glenwood 
shoreline. 


CALUMET STAGE. 

j Emergence of the floor of Des Plaines bay . — As the outlet of Lake 
Chicago was deepened by erosion, the level of the lake fell rather gradually 
from 50 feet to about “3 5 feet above Lake Michigan, where for a time 
it remained nearly constant. The conditions which seem to have deter- 
mined this halt at the 35-foot level have already been set forth. As the 
lake fell, large areas formerly under shallow water became land. The 
floor of Des Plaines bay emerged to form a broad marshy plain, which 
stretched south to the new “Calumet” shore at Riverside. (See Figure 
18.) Down the ill-defined slope of the bay plain, the Des Plaines river 
extended its course, with many crooks and bends, while the few creeks 
which headed on the Valparaiso moraine and were formerly tributary to 
the bay were now joined or “engrafted” to the trunk stream. Salt 
creek found a devious path eastward and southward on the new plain, 
almost failing to reach the Des Plaines, but connecting with it at the 
lake shore behind a beach at Riverside. 

This engrafting of independent streams to form a single system on 
the emerging of the Des Plaines plain, is comparable in a general way 
to the growth of the lower Mississippi system. During early Tertiary 
time a long arm of the Gulf of Mexico reached up the Mississippi valley 
as far as Cairo. Tributary to the bay w r ere several large rivers; the 
upper Mississippi and the Ohio at its head, the Tennessee on its east side, 
and the White, Arkansas, and Red rivers on the west side. Near the 
close of the Tertiary period warpings of the earth’s crust were accom- 
panied by a withdrawal of the sea from the land. The valley of the 
lower Mississippi emerged, and the several rivers united on the plain to 
form the single great river system, whose drainage area is a million and 
a quarter square miles. The Amazon system of Brazil, with twice as 
great a drainage basin, has been made in a similar way. 

The crooked path of the Des Plaines river, which was determined thus 
early by original inequalities of slope on the newly exposed bay floor, ac- 
counts in large measure for its present course and the width of the valley 
which it has excavated. While the lake stood at the Cahimet level, the 
river began its work of excavating a channel along its course, gradually 
entrenching itself below the bay plain. Later, as the lake waters fell and 
the base level of erosion for the river was lowered, the entrenchment of 
the river progressed to greater depth. The consideration of this matter 
is left for a later section. 


GOLDTHWAIT.] 


HISTORY OF THE UPPER DES PLAINES. 


75 . 


The Calumet shoreline . — The margin of the lake at this stage crossed 
the plain of the Des Plaines bay obliquely from Austin 'to Riverside. 
This portion of the lake shore is marked in some places by a beach slope 
or moderate definition. South of Twelfth street (where it crosses Austin 
a venae near the McKinley school) the ridge-like form of the beach be- 
comes more and more marked. 



An interesting geographic response to the shore topography of this 
old lake stage is seen in the many old farm houses and barns along the 

crest of the ridge. The early settlers on this poorly drained Chicago 

\ 


I 


76 


THE DES PLAINES VALLEY. 


[BULL. NO. 11 


plain located their homesteads on the dry, sandy beach ridges. A char- 
acteristic old-time farm house, now almost in ruins, stands at the corner 
of Austin avenue and Twelfth street. Numberless examples of this sort 
might be given. 

At Charles Becker’s picnic grove (Twenty-second street), where the 
La Grange trolley car crosses the beach, the characteristic profile — a 
long, gentle front slope and a short, moderately, steep back slope, is 
plainly seen. Here, as is frequently the case, the ridge is lined with old 
oak trees, and was formerly followed by a highway. From this point- 
south for a mile or more a road follows the beach (See Fig. 19). Near 
the Illinois Central railway the ridge is double. A second crest, on the 
west side of the road, stands a few feet lower than the main beach. It 
suggests, of course, that the plain northwest of the beach was formerly 
a shallow bay, and that the inner crest of the ridge is a low beach built 
by waves from the bay side of the bar; but as this plain seems to be 
somewhat above the 35-foot level it seems unlikely that it was submerged 
during the Calumet stage. 

Through the east part of Riverside the beach, if ever strongly de- 
veloped, has been effaced by artificial grading. It reappears distinctly 
west of the Chicago, Burlington & Quincy railway station, running 
southwest as shown in Figure 19. Close behind it, the Des Plaines river 
follows a deflected course from the railway bridge to the mouth of Salt 
creek. There, turning abruptly eastward around the end of the ridge 
and again sharply northward, it runs back to Riverside. The deflected 
path of the river above Salt creek is doubtless due to the southwestward 
drift of waste along the beach. Probably the Calumet beach ridge 
stretched along the lakeward border of a marsh near the mouth of the 
Des Plaines river and Salt creek. The southwestward movement of 
material on the beach prevented the river from running directly out to 
the lake, and pushed it farther and farther toward the southwest. The 
return couse of the river on the lakeward side of the beach ridge is, of 
course, of later origin, and will presently be discussed. At one place 
not far south of the railway bridge the river cuts obliquely across a 
branch crest or spur of the beach ridge. Beyond that point, however, to 
the mouth of Salt creek, its course is parallel to the old beach. One 
should realize, of course, that during later stages the river has deepened 
its course some 15 feet below the bay plain and the swamp of the Calu- 
met times. The beach ridge which deflected the river was not the high, 
conspicuous ridge of to-day, but the relatively low beach which now 
forms its crest. 

Across the river, between Lyons and McCook, there is no clear indica- 
tion of the shore of the extinct lake. The position of the Calumet shore 
may be inferred from the 35-foot contour of the Sanitary District’s map 
(Figure 19), which indicates that it bent eastward from Lyons in a long 
curve, passing around the gently sloping rock elevation east of Joliet 
avenue and returning west and southwest to the base of the long hill 
west of McCook. There it lies just down the slope from the Glenwood 
shoreline. 




STATE GEOLOGICAL SURVEY. 


BULL. NO. 11, PL. 8 



A. Young Gulley near Reed’s Woods. 



B. Calumet Beach Ridge at Summit 



GOLDTHWAIT.] 


HISTORY OF THE UPPER DES PLAINES. 


77 


On the south side of Lake Chicago the shore of the Calumet stage 
runs northwest from Blue island several miles to Summit, at the head 
of the outlet. As one approaches Summit along Archer road (the route 
of the trolley cars from Chicago city limits to Joliet, shown on the 



Fig. 19. Map of the district about Riverside and Summit (from map of the 
Sanitary district). Contour interval, 5 feet above Chicago datum. Beach ridges 
indicated by dotted pattern. 


78 


THE DES PLAINES VALLEY. 


[BULL. NO. 11 


map, Figure 19) the beach ridge is seen not far to the south, rising with 
pronounced slope 15 or 20 feet above the lake plain. Its crest is higher 
than the 40-foot contour. About a mile east of Summit, where the road 
ascends the ridge, it is double-crested ; the south, or inner crest, standing 
a few feet lower than the outer one. From here westward the ridge 
widens considerably, showing three distinct crest lines, and at Summit 
it hooks sharply around to the south, forming the gateway to the outlet 
of Lake Chicago. There seem to have been been three closely set hooks 
here at Summit, one overlapping the other ; hut the subsequent widening 
of the outlet during the Toleston stage of the lake cut away the bends of 
the hooks, leaving only their main stem to the east and their points to 
the south. The innermost extends from the turn of Archer road south- 
ward beyond the school house, with characteristic beach profile. The 
middle ridge, much less distinct, crosses Archer road just opposite the 
school house and soon dies out. Two hundred yards farther south, the 
truncated edge of the outermost ridge appears on the channel bank of 
the outlet, at the west side of Archer road. Crossing diagonally, it runs 
southward several hundred yards, and flattens out near the railway 
crossing. 

Judging from the height of the ridge, its hooked form and the con- 
tours of the Sanitary District’s map, this was a bar during the Calumet 
stage, shutting off a broad lagoon and marsh that stretched southward 
as far as Mt. Forest island. There was probably a depth of 10 feet of 
water for a mile or so behind the bar, and extending southwest past the 
Chicago Union Transfer yards, affording some wave action on the hay 
side of the ridge. Not far southwest of this, the plain rises almost im- 
perceptibly to a height slightly above the level of the Calumet stage, so 
that this district immediately north of Mt. Forest island was undoubt- 
edly a great marsh. 

On the east side of Archer road, near Mt. Forest island, may be seen 
a low beach ridge which stretches from Bethania cemetery northeast- 
ward across the fields. It is marked by a line of great gnarled oak trees 
and an old brick farm house. This beach during the Calumet stage ran 
along the southwest corner of the marsh, marking off the long narrow 
arm of the lake which led to the outlet. The gateway between Summit 
and McCook might in one sense be taken as the head of the outlet, though 
the actual river began more properly at Mt. Forest, at the head of the 
notch in the Valparaiso moraine. 

TOLESTON STAGE. 

Extension of the Des Plaines river near Riverside . — As the Chicago 
outlet once more cut down its floor, the waters of Lake Chicago again 
dropped 15 feet, to a level of 20 feet above Lake Michigan. The shore- 
line withdrew somewhat towards the present shore, and the month of 
the Des Plaines river was extended from behind the end of the Eiverside 
bar to a point near the spill-way above the Santa Fe railway bridge 
(Fig. 19). In this extension the Des Plaines was led far out of its way 
by the irregularities of the shallow lake floor. From the end of the 


GOLDTHWAIT J 


HISTORY OF THE UPPER EES PLAINES. 


79 


Biverside beach ridge, where a broad belt of slightly higher ground bor- 
dered the lake on the south, the river turned sharply northwest along 
the outer side of the beach to Biverside, where it again turned east and 
south down the slope to the plain to its new mouth above the Ogden dam. 
The board elevation at Lyons which prevented the extension of the 
river straight towards Summit, causing the return course to Biverside, 
is a rocky elevation only thinly covered with till. The limestone quarries 
of Bred Schultz are located here, near the bend of the Des Plaines. As 
no bed rock is exposed in the river bank, however, it is altogether prob- 
able that the recurving of the river to Biverside was brought about not 
by the resistance of rock encountered in the river bed, but rather by the 
initial slope of the old lake floor around the elevation. Thus the earlier 
deflection of the river' behind the Calumet beach was supplemented at 
the beginning of the Toleston stage by an opposite deflection on the lake 
plain along the outer side of the beach, producing the peculiar hairpin- 
like curve which is shown on the map (Figure 19). Salt creek, formerly 
entering the lake behind the Biverside beach in a swamp close to the 
mouth of the Des Plaines river, now became a real tributary of it. The 
volume thus added to the Des Plains system was very considerable. Salt 
creek drains an area of 110 square miles, or one-fifth as large a basin as 
the main river above Lyons. It gathers its volume from a long belt of 
low ground within the Valparaiso moraine. The current of Salt creek 
where it enters the Des Plaines at the beginning of the sharp bend 
strongly influences the direction of current of the trunk stream at that 
point, holding it off from the outer bank, which it would otherwise be 
actively trimming, and thus tending to maintain the bend in a fixed 
position. 

Reneivecl trenching of the valley . — The lowering of the lake to the 
Toleston stage was equivalent to a lowering of base-level for the Des 
Plaines river about 15 feet. So, with steepened slope, the river was in- 
spired to sink its channel below the grade already established during the 
Calumet stage, and deepened its trench to a level not far above that of 
the present valley floor. A more detailed account of the trenching and 
the associated shifting of the crooks and bends in the river will presently 
be given. 


The Toleston shoreline . — The shoreline of the Toleston stage is 
marked, between Hawthorne and the river, by a low but distinct beach 
ridge which rises seldom more than 10 feet above the low lake plain. 
On the west side of the river a distinct bluff not over 10 feet high ap- 
pears along the base of the gently sloping hillside south of Lyons. Fad- 
ing awa}^ as it nears Joliet avenue, the shoreline is almost lost on the 
old lake floor near McCook, and does not again appear at all plainly on 
the west side of the old outlet. 

A short distance east of Summit the outer slope of the great Calumet 
beach ridge was cut away by the lake to form a low cliff, in the Toleston 
stage. Just northeast of the village of Summit this is replaced by a 
broad, flattish beach ridge of gravelly constitution, which stands only 
a few rods north of the higher Calumet ridge, where the latter is ex- 
tensively opened at a gravel pit (See Fig. 19). Here is a unrticularly 


80 


THE DES PLAINES VALLEY. 


[BULL. NO. 11 


good place to see the beaches of the 35-foot and 20-foot stages close to- 
gether, and to study the contrasted features of beach ridge and shore 
cliff. The stratification of the beach gravels of the Calumet ridge is 
especially well shown in the gravel pit. 



Fig. 20. Part of Lake Chicago during the Toleston stage. (Modified from 
Alden.) 

From Summit southward the east side of the outlet is marked for 
several miles by a steep straight bluff, which lies just west of Archer 
road and is plainly seen from the car window most of the way to Willow 
Springs. The bluff is about 15 feet high, rising from the 20-foot con- 


goldthwait . ] HISTORY OF THE UPPER DES PLAINES. 81 

tour to the level of the Calumet lake floor. It was cut by the outflowing 
river, probably at the time when the removal of the sill of bed rock at 
Lockport caused the river to saw down its bed along its entire course 
above Lockport. 

SUBSEQUENT CHANGES LEADING TO FORMATION OF LAKE MICHIGAN. 

The manner in which the lake fell from the Toleston or 20-foot level 
to a level below the present Lake Michigan, and then rose to a level about 
12 feet above it has already been told. It was while the lake stood at 
the 12-foot level that the broad reef of sand was constructed between 
Lincoln park and South Englewood, shutting off the Chicago outlet. 
Because of this, the district east of Summit, including the greater part 
of the city of Chicago, was probably a great shallow marsh, with only 
slight and sluggish drainage westward through the abandoned outlet! 

The series of changes which led to the disappearance of Lake Algon- 
quin, to the complex history of the Nipissing great lakes, and finally to 
% the present chain of lakes with the single outlet through the St. Clair 
river, has been given in the preceding chapter, just referred to. So far 
as the history of the Des Plaines river is concerned, we may ignore the 
details of these changes and consider simply how the lowering of the 
lake from the 12-foot level to the present one affected the river. As the 
lake fell, the slope of its floor, now newly exposed near Summit, was 
hardly sufficient to direct the Des Plaines river southwestward into the 
head of the old outlet. At the bend which the river now makes there, 
near Ogden dam (See Fig. 19), a well defined slough, formerly known 
as Mud lake, leads eastward to the south branch of the Chicago river. 
It marks a line of escape which has been used time and time again by 
the Des Plaines during floods. Here was the old Indian portage, where 
Marquette and other early explorers, at the time of a spring freshet, 
could paddle their canoes from Lake Michigan to the headwaters of the 
Illinois. It is not at all improbable that at one time the Des Plaines 
river discharged wholly through this slough, into Lake Michigan. If so, 
its southwestward course (which we have called the Mower Des Plaines)” 
is a very recent one. The natural divide, east of Mud lake, on the smooth 
plain near Kedzie avenue, may have been built, as Mr. Lyman E. Cooley 
suggests, by silts from the river, collected behind a beaver dam. 

EXCAVATION OF THE VALLEY. 

It has already been explained how the emergence of the smooth floor 
of Des Plaines bay when the lake fell from the 50-foot to the 35-foot 
level was accompanied by the extension of the river from near Franklin 
Park southward to Riverside. Many crooks and bends were caused by 
faint irregularities of slope of the newly exposed surface. The slope of 
the bay plain from the 50-foot contour near Franklin Park down to the 
35-foot level at Riverside is exceedingly gentle, a fall of 15 feet in 12 
miles. This is somewhat steeper, however, than the present slope of the 
Des Plaines river, which falls only 5 or 6 feet in the same distance. 

— 6 Gr 


82 


THE DES FLAINES VALLEY. 


[BULL. NO. 11 


During the Calumet stage, then, with an initial slope of about l 1 /^ feet 
per mile, the river may have reduced its slope to as low a grade as it 
now possesses — half a foot to the mile, by sinking its channel a few feet 
below the bay plain. The river, then, during the Calumet stage, might 
have deepened its trench several feet below the level of its broad valley 
floor. The subsequent drop from Calumet to Toleston level, while it ex- 
tended the mouth of the river only a short distance, reduced its base-level 
15 feet, i. e., made it possible for the river to cut 15 feet lower, by steepen- 
ing its slope and increasing its velocity and its efficiency for deepening 
its bed. Again, when the lake waters fell from the 20-foot mark to 
essentially the present level, laying bare the plain between Riverside and 
Summit and allowing the Des Plaines to turn southwest down the floor 
v _ the abandoned outlet channel, the local base-level was lowered ; erosion 
was revived, and this revival was transmitted upstream, causing a deep- 
ening of the channel. In the subsequent interval, the river has cut its 
valley about 10 feet below the Toleston level, near where its mouth lay 
during the Toleston' stage. Farther up, however, the deepening has been 
much less, because it has cut down to bed rock, revealing the surface of 
the ledges at three places — >(1) a few rods below the Ogden avenue 
bridge, (2) just below the Riverside dam, and (3) on Salt creek just 
above its junction with the Des Plaines. Since the sill of limestone at 
Riverside stands almost as high as Toleston level, it seems to have pre- 
vented the f ull amount of deepening above Riverside after the Toleston 
stage. 

If such is the case, there have been three steps in the excavation of the 
trench-like valley above Riverside. (1) During the Calumet stage of 
Lake Chicago a shallow, winding trench was cut below the bay plain, 
with low grade appropriate to Calumet base-level. (2) With the drop of 
the Toleston stage, a second period of deepening began, which probably 
reduced the floor of the trench to Toleston base-level. (3) Since the -low- 
ering of the lake from the Toleston to the present level there has been a 
further deepening of the channel, amounting probably to only a few 
feet; for the process has ben effectively checked by the ledges at River- 
side. 

Bearing in mind these points of erosional history of the upper valley, 
we may now seek to explain the peculiar details of the valley that has 
been excavated. It should be remarked in the first place that the contour 
map of this district published by the IT. S. Geological Survey (River- 
side quadrangle), with its rather small scale of one mile to the inch, 
lacks details; so the expression of the trench-like valley on this map is 
quite misleading. It is shown as a narrow, winding trench which follows 
closely every crook and turn of the river. On the larger and more de- 
tailed contour map drawn by the Sanitary District (and copied in part 
in Fig ires 17 and 19) the true form of the valley comes out distinctly. 
It is a trench of considerable width, not infrequently ten times as broad 
as the channel which swings across its floor from side to side in imper- 
fect meandering fashion. Compared with the crooked river channel the 
trench of the valley is relatively straight, its two banks constricting the 


GOLDTH WAIT . ] 


HISTORY OF THE UPPER DES PLAINES. 


83 


turns and sharply defining its meander belt. Where the river impinges 
against one of its bluffs there is a steep bare-faced exposure of glacial 
drift and frequently toppling trees, which testify to the lateral sawing 
of the river and the constant widening of its trench. 

Perhaps the most instructive view of this lateral cutting is to be had 
at the Madison street bridge, near Harlem. (See Fig. 17.) On the north 
side of the bridge the river is rapidly trimming back its left bank, ex- 
posing the compact glacial drift in a steep 15-foot bluff. As fast as the 
river saws at the base of the bank, the bowlder clay,, loosened by frost 
or by percolating water and its own weight, slides into the river, and is 
carried down stream. Thus a nearly perpendicular bank is maintained, 
as steep as the unsupported clay will stand. Just across the street, at 
Concordia cemetery, the same bank has been protected from lateral 
erosion by a high fence of posts and planks and walls of loose rock. 
While, because of this protection, the river has not cut outward on its 
bend at the cemetery, it has trimmed away fully 25 feet just above the 
bridge. 


Even at those points where the bluff is removed from the river, on the 
opposite side of its valley, the slope is as a rule steep and straight, and 
the valley floor at its base is often marked by a shallow slough, formerly 
occupied by the river when it trimmed and steepened the bluff. (See 
contour on Fig. 17.) 

A very little study makes it clear how the trench has been cut so much 
wider than the river channel and everywhere just as wide as the meander 
belt. When the river first found its way across the bay plain, a surface 
exhibiting frequent inequalities of slope, it followed many crooks and 
bends much like those of the present course. It- is a well known prin- 
ciple that at each bend in a crooked channel the current of river swings 
toward the outside of the curve and in consequence there is a tendency 
for the river in time of high water to trim away its outer bank. This 
process is known as “lateral planation.” At the same time, the river de- 
posits sediment on the inside of the curve where the current is weak. 
The combined process is known as “cut and fill ” How, it follows from 
this deflection of the current from side to side that in rounding a bend 
or loop the river does most of its cutting on its down-valley side and 
most of its filling on the up-valley side. The result of this progressive 
growth. is the constant migration of the bends down-valley. Figure 21 
illustrates the effect of this migration on the outline and width of the 
valley. As the bend thus shifts its position, the point of attack against 
the bank likewise shifts down valley, so that a straight bluff is trimmed 
one one side and a pointed spur developed on the opposite side. (Fig. 21 
FI.) Slowly this spur is worn away as the upper bend encroaches on it 
(Fig. 21, II, III and IV), and bv the time' this second bend has passed 
the starting point of its predecessor both sides of the valley have been 
trimmed back. There remains a flat-floored, straight-walled trench, 
whose width corresponds to the meander belt of the river. It necessarilv 
follows, also, from the deflection of the current toward the outer bank, 
that as the river cuts downward and outward the bends will increase in 
size, and to that extent the meander belt will be widened. While the 


84 


THE i)ES PLAINES VALLEY, 


[BULL. NO 11 


bends are shifting and banks are being trimmed, the filling process on 
the inner bank covers the floor of the valley with stratified sediments 
and a flood-plain is formed — a flat valley bottom, usually above the 
river level but submerged whenever the river is swollen by rains suffici- 
ently to fill its channel to the brim. 

During low-water stages the river does very little work. It is too weak 
to carry any significant amount of sediment. Even at ordinary stages 
the river works slowly and laboriouslv; but during floods, when the 
volume of the stream is considerably increased, its power as a carrier is 
enormously increased, and it is then that the cut-and-fill process is 
effective and flood-plains are constructed. It may be demonstrated that 
the transporting power of a river varies as the sixth power of its velocity 
and that its velocity varies as the cube root of the volume, if the shape 
of the channel be disregarded. In other words, the carrying power varies 



Fig. 21. Diagrams showing the development of a straight walled, flat floored 
.valley, by the trimming away of spurs as the bends of the stream migrate down- 
valley. The river is flowing in the direction of the arrow. Four stages are 

shown. In I ai, 61, cl, are three bends, which lie between three alternating 

spurs, x, y, z. The valley bottom is narrow — no wider than the stream. In II the 
tendency of the stream to cut on the down-valley side of each bend has shifted 
ai, 61, and cl to the positions a2, Z>2, c2, leaving stretches of straight valley walls, 
ai-a2, bi-b2, cl- d. Across the river at each bend a portion of the up-valley side 
of each spur, x, y, z, has been trimmed away, sharpening these spurs. A flat floor, 
of variable width (un-shaded) has thus been produced. In III the process has con- 
tinued. The bends have migrated down-valley to «3, b 3, c3. The stretches of 

straight valley wall have been lengthened, al-a3, &1-&3, cl-c3. The spurs x, y, z, 

have been half consumed by the trimming away of their up-valley sides. The 
valley floor has been much widened. In IV a still later stage has been reached 
The bend a has shifted down-valley nearly to the position c, extending the- straight 
wall al-a4 nearly far enough to consume the spur y. This spur is now very blunt, 
and will be wholly consumed by the time bend a has migrated down-valley to the 
very position which the next bend below it, c, originally had. The other spurs, 
x and z, have been similarly blunted, and will soon be consumed. The valley will 
then .be straight sided, flat floored, and as broad as the swing of the bends, i. e., as 
the meander belt of the river. 

as the square of the volume. If, then, the flood volume of a river is 
eight times its normal volume, its velocity is twice as great, and it is 
able to move fragments sixty- four times as large as at the ordinary stage. 
The extreme low water volume- on the Des Plaines, as measured at 
Riverside, in 1887 was 4 cubic feet per second; the flood volume of the 
same year, 10,324 cubic feet. What an enormous difference, therefore, 
exists in the carrying power and sculpturing power of the river between 
these extreme stages ! We may well believe, then, that just as the 


GOLDTHWAIT . ] 


HISTORY OF THE UPPER DES PLAINES. 


85 


average yearly flood greatly exceeds the ordinary river stages in its work- 
ing capacity, the occasional extreme flood greatly exceeds the normal 
flood in its destructive and constructive work. Although extreme floods 
commonly occur only once in several years, and at irregular intervals, 
the flood-plains which they build are usually very prominent features 
of the valley. During the interval between extreme floods (usually 5 to 
10 years in the case of the Des Plaines), the normal yearly floods permit 
the partial destruction of the high-level flood-plain and the development 
of a lower floor at the level of ordinary high water. The erosion of the 
river along the banks of its channel aids somewhat in tearing down the 
high-level plain; but before the upper flood-plain has been wholly de- 
stroyed by lateral planation, another flood of unusual proportions occurs, 
and the high flat is reconstructed. One of the most striking features of 
the Des Plaines trench is a terrace which stands several feet above 
ordinary high water and is covered only by extreme floods once in several 
years. The infrequency of submergence of this terrace is shown by the 
fact that many picnic groves with their small buildings, and a group of 
cottages at the Methodist camp grounds at Des Plaines are located upon 
it. Rarely do the spring freshets rise high enough to cover it, but when 
they do much damage is done. Stretches of bottom land a few feet lower 
than the terrace and always between it and the river mark the level of 
ordinary annual floods. 

The Des Plaines river illustrates remarkably well the features just 
described and figured. Migrating bends, straight-trimmed bluffs and 
broad flood-plain are exhibited especially well between Maywood and 
Riverside. (Figure 17.) The bends of the Des Plaines are as a rule 
obtuse rather than acute, hence the trench formed as they have sunk 
and moved down valley is rather narrow when compared with the few 
places where the bends are more circular (e. g. the S-shaped bend two 
miles above Maywood and a series of curves above Des Plaines village). 
There the more rapid enlargement of the curves together with their 
down- valley migration has formed a trench 400 to 500 yards wide. 

When studied in connection with a large river like the Missouri or 
Mississippi, the Des Plaines is found to be deficient in the regularity 
and symmetry of its bends. Close study will also show that its valley 
is not wide enough in proportion to its channel to compare with rivers 
•which have reached an advanced or mature stage of development. The 
widening of a river valley continues as a rule until the meander belt is 
at least sixteen times as wide as the river channel. By that time the 
crooks have turned into loops of great beauty and symmetry, and the 
trimming of the bank no longer occurs at every bend. The meander 
becomes more and more looped, the inclosed lobes of flood-plain match- 
ing together in dove-tailed fashion. The necks of the pear-shaped 
spurs grow narrower and narrower by the cut-and-fill process, until at 
last (usually in time of flood) the river cuts through the neck, gaining 
a shorter course, and the long loop is abandoned, becoming either a 
slough or an ox-bow lake. These old “meander scars” are gradually 
effaced by deposits of sediment during subsequent floods. 


I 


86 THE DES PLAINES VALLEY. [bull. no. 11 

As regards its stage of development, therefore, the Des Plaines may 
be called a youthful river. In its infancy a crooked stream, running 
along the newly exposed bay plain, it was enabled to lower its channel, 
and in so doing sent a succession of loops moving down valley. By them 
its valley floor has been widened and its valley walls trimmed back. It 
is still at work at these tasks, broadening its valley by lateral planation, 
seeking to gain a floor sufficiently wide on which to turn and twist in 
closed loops like the larger and older “father of rivers’" to which it is 
tributary. No longer exactly “young,” it is still “youthful.” Another 
interval of time, as long probably as that already elapsed in the river’s 
history, will be required for the river to reach full maturity. 

DEVELOPMENT OF TRIBUTAPJES. 

The development of tributaries to the upper river has already been 
partly discussed. The larger tributaries, like Salt creek and Higgins 
creek, which head on the Valparaiso moraine and cross the old floor of 
Des Plaines bay to reach the main river, have already been spoken of. 
They are consequent upon the drift surface, having followed the guid- 
ance of initial slopes. Along their lower courses the tributaries south 
of Franklin Park were extended and engrafted on the Des Plaines as 
the bay plain emerged, at the close of the Glenwood stage of Lake Chi- 
cago. As previously remarked, these tributaries are confined almost 
wholly to the west side of the Des Plaines. The low till ridge that forms 
the eastern side of the valley does not gather and shed enough water to 
support permanent streams of any considerable length. 

Some of the larger of these tributary creeks, near where they join the 
Des Plaines, have a remarkably mature aspect ; for they meander broadly, 
with horse-shoe shaped loops. One of the most accessible, as well as one 
of the prettiest examples is the creek which enters the river north of 
Maywood, opposite Theiler's park. (See Figure 17.) Its valley floor, 
unlike that of the Des Plaines, is much wider than the meander belt, 
and the meanders approach in shape those of the Mississippi. In these 
respects, the tributary looks more mature than the trunk river. Srcch a 
condition is quite abnormal and demands explanation; for we should 
expect the trunk stream to have reached a more advanced stage of de- 
velopment than any of its tributaries. The explanation seems to be 
found in the influence which strong floods of the main river have on the 
flood plain of the branch stream. It is very apparent that when the Des 
Plaines, gathering a large volume from its long basin during a spring 
thaw or a heavy rain, is swollen and overtops its flood plain, it invades 
the lower end of the tributary valley, backing the waters up. In this 
bay-like extension of the trunk valley, during the flood, silts, chiefly 
from the main river, may be laid down and a flood plain built up to 
the back-water level. A flood-plain constructed under such conditions 
would be flatter than one formed by the tributary itself, flowing down- 
grade into the main river; and on such an over-flattened plain, after the 
flood subsided, the tributary would be apt to meander more widely than 
on the sloping floor of its upper course. The fact that the “mature” 


GOLDTHYVA1T. J 


HISTORY OF THE UPPER DES PLAINER. 


87 


loops seem to be restricted to the lower courses of the tributaries favors 
the idea that they are due to back-water influence. 

This class of tributaries might be called “original/* to distinguish 
them from another, newer group of “secondary** origin. 

The manner in which the second class of tributaries start to grow may 
be studied to advantage wherever the main river is bordered by a freshly 
trimmed bank ; as, for instance, at the Madison street bridge. It will be 
observed here that the clay slope is carved by innumerable little gullies, 
the work of recent rains. Such of the gullies as chance to find an ad- 
vantageous place for headward growth, either because of softer ground 
structure than their neighbors or because of an initial depression near 
their heads, from which they may receive more than an equal share of 
the run-off, will grow more rapidly than those on either side. In the 
incipient stages, such differences in rate of growth are slight; the ad- 
vantages are small, and largely accidental. The presence of a tree root 
that will turn the rain wash away from one gully and towards its neigh- 
bor may be of prime importance in determining which shall grow. With 
growth, both lateral and headward, the favored gullies rapidly swallow 
up or dwarf their neighbors. Natural selection operates as truly here 
as in the realm of life. Of the hundreds of gullies on a newly rain- 
carved bank, only one or two are destined to grow to conspicuous size; 
and but one out of many thousand will develop into a large ravine. It 
should further be said that of the gullies carved by side wash down a 
river bank there is wholesale destruction at the hands of the river itself ; 
for it as a rule trims away its bank faster than most of its side gullies 
wear back their heads. This, together with the competition among the 
gullies themselves, explains the delay in the development of tributary 
ravines. 

North of the Madison street bridge, in the picnic grove and woods, 
may be found gullies of “secondary** tributaries in various stages of 
growth. Short, steep, Y-shaped gullies with bare sides occur close to the 
bridge, where the freshly trimmed river bank is being scoured by rains. 
About an eighth of a mile north of Madison street is a small ravine, 
which is some 300 yards long and at its mouth is about 20 feet deep. 
It has no branches, and is remarkably straight, yet towards its mouth 
it bends back and forth between a set of interlocking spurs, similar to 
those described on pages 83-84. Besides the examples near Madison 
street, there are well developed “secondary** tributaries in the northeast 
part of Mavwood, two of which are shown by contours on the map Fig. 
18. 


These “secondary** tributaries, formed by the headward growth of 
lateral gullies, are few, short, and exceedingly simple in plan. They 
have few or no branches. Like other features of the valley they are 
marks of the youthful condition of the Des Plaines system. 


88 


THE DES PLAINES VALLEY. 


[BULL. NO. 11 


CHAPTER VII. 


FLOODS ON THE DES PLAINES RIVER. 


THE UPPER RIVER. 

The Des Plaines river is subject to floods of unusually long duration, 
as compared with other rivers of its size. Each spring, as the snow melts 
rapidly out of its basin, the river is swollen by the additional volume, 
and rises several feet above its normal level. A portion of the valley 
floor is thus flooded for days or even weeks. 

In his paper on “The Illinois river basin in its relations to sanitary 
engineering,^ 1 Mr. L. E. Cooley expresses the view that the peculiar 
shape of the basin — narrow from east to west, and sixty miles long from 
north to south above Riverside (See Fig. 1) makes the floods' on the 
Des Plaines last longer and rise less than they would in an equally 
large basin of different shape. When a warm spell comes in the spring, 
attended perhaps by rains, the snow and ice are rapidly melted from 
the frozen ground, and on all sides water runs down the slopes into 
the river. The melting begins a little sooner at the south end of the 
basin and advances northward up the valley to the head-waters. Ac- 
cordingly, “after heavy precipitation the maximum flow comes from 
the immediate body of the watershed, while the flow from the head- 
waters will come in to sustain the volume and to prolong the flood. 
The melting of the snow in the north portion of the basin will maintain 
the flow for several days after it has melted and run away from the 
south portion.” 

In this respect the Des Plaines river is the antithesis, on a small 
scale, of the Red river of Minnesota and Dakota, which runs towards 
the north for several hundred miles, and chiefly on that account is sub- 
ject to very high and destructive floods. 2 


1 Appendix to a report on “Water Supplies of Illinois.” Preliminary report to 
the Illinois State Board of Health, pp. 49-81, 1889. 

2 One of these occurred in the spring- of 1897. During- the preceding- winter 
several feet of snow had accumulated on the ground, around the headwaters of 
Red river. Early in April, in the course of only two or three days, all this snow 
was melted off by a warm wave. The immense volume of water thus let loose 
quickly found its way over the frozen ground into the river, swelling it beyond all 
proportions. Farther down the river, i. e., farther north, where the arrival of the 
warm wave was somewhat delayed, the ice had only begun to break up when the 
flood and floating ice from the headwaters were precipitated upon it. Ice jams 
were formed, and the Red river was dammed back, at Fargo and Morehead, until 
it was 12 miles wide. 


GOLDTHWAIT.] 


FLOODS ON THE DES PLAINES. 


89 


While the meridional length of the Des Plaines basin is an interest- 
ing fact, when seen in this light; and while it may operate to some 
extent in prolonging floods; it seems hardly likely that because of the 
difference of latitude alone the snow would melt sooner at its south end 
than at its north end. The sun’s rays are hardly one degree higher 
at the former than at the latter. Certainly the difference would not 
cause a delay of several days in the melting process. The explanation 
of the delay in the northern portion of the basin; about the head- 
waters; is probably to be found in the greater acreage of forest there and 
the greater diversity of surface; affording more frequent shaded slopes. 

Mention has been made of the spring freshet of 1674; in which the 
Des Plaines discharged so much water eastward towards Chicago that 
Marquette and his two companions were forced to abandon their hut 
beside the Chicago river; and were enabled to cross the divide in canoes 
a few days later. Another flood of this sort; accentuated by ice jams 
near Summit; caused much damage to shipping and bridges on the 
Chicago river in 1849. 

One of the most extraordinary floods of which there are accurate 
measurements was in April; 1881. Mr. Cooley tells of it in these 
words. 1 “The flood maintained its height for nearly four days; and 
lasted about twenty-one days. The ground was practically saturated 
when winter set iii; and about one foot of water in the shape of ice and 
show accumulated; and all ran out or melted during three weeks, at a 
temperature a little above freezing point and without material rain. 
The southern portion of the watershed was entirely bare before the 
northern snows began to melt. For this reason, the flood volume held 
measurably constant even toward the sources of the stream, until the 
snow at headquarters began to be exhausted. The conditions presented 
in this flood are of extraordinary occurrence only.” On April 21st 
the flood reached its maximum height at Riverside, the discharge over 
the dam amounting to 13,500 cubic feet per second. The river here 
was nearly six feet above its low-water level. At the Ogden dam the 
river rose more than seven feet above its low-water mark, giving an 
overflow there 3^2 feet in depth, so that a considerable part of the flood 
waters found their way ,to the Mud Lake district and Lake Michigan 
instead of down the lower Des Plaines. The proportion of water which 
turned eastward was abnormally great on April 9th and 10th, because 
of an ice gorge on the river. Nearly all the water that passed Riverside 
on these two days was diverted towards Lake Michigan. At Kedzie 
avenue the volume flowing through the Ogden ditch, from the flooded 
slough into the Chicago river, was as follows : 


Feb. 10th 7,800 cu. ft. per second. 

(cf. with the 8,00 feet at Riverside.) 

Feb. 11th 4,636 cu. ft. per second. 

Feb. 14th 1,625 cu. ft. per second. 

Feb. 18th 4,000 cu. ft. per second. 

Feb. 9th 3,042 cu. ft. per second. 


1 Op. cit., p. 74. 


I 


90 


THE DES PLAINES VALLEY. 


(.BULL. NO. 11 


The figures determined at three stations show that the flood was 
double, decreasing between the 10th and 16th and rising again on the 
19th. Regarding the effect of the overflow across Ogden dam in dimin- 
ishing and regulating the flood along the lower Des Plaines, Mr. Cooley 
says i 1 “When the water in the Des Plaines stands at the crest of the 
dam, the flow down the Des Plaines is 800 to 1,000 fieet per second, 
depending upon whether the water is falling or rising, or on the con- 
dition of vegetation in the ‘12-mile level/ Above this volume, the 
proportion escaping to Chicago increases rapidly with the height of 
flood, and for this reason the floods passing Joliet are more uniform in 
volume, one year with another, than at Riverside/ 7 In large floods 
fully half the water goes over the dam of Lake Michigan. The crest 
of the dam is 11.7 feet above the lake (Chicago datum for Lake Mich- 
igan, 580 feet above the sea.) In low water the river is 3.7 feet below 
the dam. 

Another unusual .flood occurred early in February, 1887, reaching a 
maximum height at Riverside on the 9th. 2 3 The volume of discharge 
as measured at Riverside and Joliet on different days is as follows: 

Riverside. Joliet. 

Cu. ft. per sec. Cu. ft. per sec. 


Feb. 9th 10,324 

Feb. 10th 8,000 

Feb. 11th 7,000 5,775 

Feb. 16th 2,000 1,460 

Feb. 19th 5,374 5,385 


Comparing figures at the two stations for the 11th and the 16th, it 
is seen that a large fraction of the volume which passed Riverside escaped 
over the Ogden dam to Lake Michigan, diminishing the flood at Joliet 
very materially. 

According to Mr. Cooley, an extraordinary flood, with discharge 
of upwards of 10,000 cubic feet per second at Riverside, occurred every 
five or six years between 1840 and 1890. Of the fifty-three floods 
that occurred between 1834 and 1890, thirty-eight were in February, 
March, or April, and the majority associated with the spring breakup. 
“The ordinary yearly flood as deduced from marks on the Lyons dam 
is 6,000 to 7,000 cubic feet per second/ 73 

At the Fullersburg dam on Salt creek several extraordinary floods 
have given a discharge of about 2,800 cubic feet per second. On Feb- 
ruary 10th, 1887, the volume was 2,860 cubic feet. If the volumes of 
floods on Salt creek, compared with those on the Des Plaines, were in 
direct proportion to the areas of the respective basins, the flood at 
Riverside on February 10th should have been over 16,000 cubic feet 
instead of 10,324. The failure of the flooded Des Plaines to attain 
a volume proportional to that of Salt creek is thought by Mr. Cooley 
to he due to the greater meridional length of the main basin, in which 
the melting of snow advances northward day bv day, prolonging and 
equalizing the flood. 

1 Op. cit., p. 73. 

2 The source of the information here presented, on the floods of 1881 and 1887, 
is Mr. Cooley’s report, previously cited. 

3 Op. cit., p. 73. 


GOLDTHWAIT.J 


FLOODS ON THE DES PLAINES. 


91 


The dry-weather volume of the Des Plaines is extremely small; for 
the river has not cut down its bed sufficiently below permanent ground- 
water level, and must get its supply almost wholly from surface run-off. 
In 1887 the discharge at Biverside was diminished to four cubic feet 
per second, as contrasted with 10,324 feet in the February flood of the 
same year. For five months the discharge did not exceed seventeen feet 
per second. Although the river has been known to be even lower than 
this it has never run dry. Salt creek, however, was dry at Fullers- 
burg in 1887. 

The effects of settlement of the basin in changing the height and 
direction of the floods from their original and natural condition has 
been pointed out by Mr. Cooley. During the settlement of the valley, 
the clearing away of timber and the draining out of the bogs and 
marshes by systematic trenches largely destroyed the natural reservoirs 
and regulators of floods, allowing a more immediate run-off; conse- 
quently the .floods now are higher and of shorter duration. The flow 
of the river during the year is less uniform, and low-water lasts much 
longer than formerly. These effects are even more strongly felt on 
the Kankakee river, where broad marsh lands have been reclaimed. 

THE LOWER RIVER. 

On account of the usual diversion of a large fraction of the flood 
waters by the Ogden dam at Summit, the floods which are conspicuous 
above Summit are usually of minor concern to the property owners on 
the lower course of the river. As the flood rises higher and higher 
above the Ogden dam, a larger and larger fraction of it overflows 
toward Lake Michigan. So, at Lemont, Lockport, and Joliet the floods 
as a rule are lower than at Biverside, and more uniform from year to 
year. The normal extreme flood at Biverside (as computed by Mr. 
Cooley) is nearly twice that at Joliet (12,000 and 6,300 cubic feet re- 
spectively.) 

Measurements on the dam at Joliet determine discharges during ex- 

o o 

traordinary floods as follows : 

1877 (April 7th) 6,410 cu. ft. per second. 

1881 (April 21st) ..6,550 cu. ft. per second. 

1883 (Feb. 16th) .. 6,370 cu. ft. per second. 

1887 (Feb. 11th) 5,775 cu. ft. per second. 

In the flood of April, 1881, the highest for thirty-three years (up to 
1890), the water was 3.75 feet high on the Jackson street dam at 
Joliet. This city, however, does not always escape floods. Local cloud- 
bursts, flooding the tributaries east and north of the city on the Val- 
paraiso moraine, occasionally cause much destruction of property in 
Joliet. One of these occurred on August 10, 1867, which flooded a part 
of the city and in a few hours caused much damage. 

The worst flood within the memory of the townspeople occurred at 
about midnight June 2nd and 3rd, 1902. A storm began about 9:00 
o’clock in the evening, increasing to a heavy downpour which was ac- 
companied by hail. Motormen were driven from the fronts of their 


92 


THE DES PLAINES VALLEY. 


[BULL. NO. 11 


cars by the hailstones. By midnight the water in the drainage canal had 
risen several feet. The old slough which lies between Eastern avenue 
and the Alton railway (in the heart of the city) was a raging torrent. 
The northeast portion of the city north of Columbia street became a 
temporary lake. The greatest inundations, however, were along Hick- 
ory creek, in the section known, as Brooklyn. The water poured over the 
Hickory creek dam at the red mill three or four feet deep, and a por- 
tion of the dam at last gave way. The Union elevator was surrounded 
by a lake, and its lower portion flooded ; but no grain was destroyed. 
A bridge near by, on the Michigan Central spur track, was washed out. 
On Brooklyn, Iowa, and Mississippi avenues, the waters flooded the 
sidewalks and poured through basement windows, filling cellars and in 
some cases invading even the living rooms on the ground floor. Houses 
were partially wrecked as their foundations were undermined. One 
small house was swept along several blocks and lodged against the 
Second avenue bridge. The darkness of the night magnified the con- 
fusion and horror of the scenes. People turned out long before daylight 
with boats, ladders, and rigs for the relief of the imprisoned ones, and 
the fire and police departments responded to the emergency. On Mc- 
Donough street a horse and wagon carrying six people to some place 
of refuge was overwhelmed by the current, and two of the passengers 
were drowned. Many others had narrow escapes from drowning. It 
was feared that the big dam at Jackson street would go out, but it did 
not. 

The railways were among the heaviest losers from this flood. The 
Bock Island railway bridge over the Des Plaines swung 17 inches out 
of position, a supporting pier being washed out. On the Michigan 
Central the transfer yards were destroyed. The car sheds of the street 
car company were flooded, and the motors of many cars ruined by 
water. Stove works and mills suffered likewise from inundation. Mer- 
chants within the lower portion of the city lost heavily of goods stored 
in basements. A local newspaper estimated the damage at over $500,000. 
For several hours Joliet was cut off from the outside world. Ho trains 
passed through the city until the following morning. 

At Lockport the small creeks which drain the bluffs were veritable 
torrents, tearing away fences, bridges, and even stone walls; destroying 
gardens and sweeping the debris into the Illinois-Michigan canal so 
fast that it was choked up and overflowed its banks. In this way the 
west side of the town was flooded and the colored people driven from 
their homes. The Barrows Lock company suffered damages of about 
$2,000. At Borneo the quarries were filled to the brim, and the farmers 
lost crops and young stock. The Santa Fe tracks were blocked until the 
following evening, delaying the mails. 

There were two washouts on the Bock Island railway above Joliet, on 
Hickory creek. At Hew Lennox, bridges and culverts were damaged to 
the extent of $1,500. At a washout on the track just east of the depot 
the night train on the Bock Island barely escaped a wreck. The flood 
of 1902, the highest for many years, was quite abnormal, occurring, as 
it did, in June, in response to a local cloud-burst. 


STATE GEOLOGICAL SURVEY 


BULL. NO 


PL. 9 


. 11 


9 




Effects of a Recent Flood on Hickory Creek, 



GOLDTHWAIT.] 


FLOODS ON THE DES PLAINES. 


93 


A more typical flood took jDlace on January ID, 1907, when, during a 
temporary thaw and rain, Hickory creek overflowed its banks through 
the city and the water on the Des Plaines rose within a few inches of 
the top of the embankment. Weak points on the retaining wall above the 
Economy plant were hastily reinforced, and the dam at the controlling 
works was raised to lessen the flow. Brooklyn was again under water; 
cellars were flooded, furnace fires extinguished, and fuel rendered use- 
less. The storm was accompanied by high winds that wrecked the houses 
where foundations had been loosened by the floods. Furniture and 
personal property was hurriedly moved to places of safety. The climax 
of the flood was reached about 8 p. m., when a cold- wave began to check 
the discharge. The waters slowly fell as the little headwaters and side- 
slopes of the Hickory creek system were gradually frozen. At the same 
time the occupants of many houses found their cellars filled with 3 to 
5 feet of water and their fuel inaccessible. Suffering from cold sup- 
plemented the direct injury from floods. All the railways were blocked. 
At several places between Joliet and New Lennox, the Pock Island 
tracks were under water. 

After such a flood as this there are many interesting things to observe 
on the recently submerged flood-plain. Some of the drift-wood and rub- 
bish which was swept down the valley has been caught by bushes and 
trees that grow on the flood-plain, forming great bunches of floatsam as 
high as the flood level. On Hickory creek below New Lennox, where 
the photographs (Plate 9) were taken, two months after the flood of 
January, 1907, the rubbish heaps indicated a rise of the water 7 feet 
above ordinary level. In the lee of each of these rubbish-laden bushes the 
turf on the floor-plain had been gullied out by the eddying currents. 
A lofty elm tree a little below New Lennox had been swept down 
stream, its branches trailing along behind it and ripping long grooves 
in the flood-plain surface. (See Plate 9, A.) Close to New Lennox sta- 
tion a smaller type, stranded in the bed of Hickory creek, had within two 
months after the flood caused the. construction of a considerable bar of 
sand in mid-channel. The scattering of fresh shingle over large tracts 
of the grassy floor-plain in some places and the tearing away of the old 
structures in others, after floods like this, shows how far from stable is 
the course of the river channel. 

Recent ditching of marshy areas at the head waters of Hickory creek, 
near Tinley park and elsewhere, in order to make them available for 
farming, may be expected to affect the height and duration of floods as 
already discussed in the preceding section. The more extensively 
swampy conditions are replaced by definite lines of drainage the faster 
will the run-off occur. Floods will rise higher but they will not last so 
long. 


94 


THE DES PLAINES VALLEY. 


[BULL. NO. 11 




APPENDIX. 


SUGGESTIONS FOR FIELD TRIPS. 


The object of this appendix is to suggest some of -the more accessible 
and more interesting localities in the lies Plaines valley where physical 
features may be studied to advantage by the amateur or by the teacher 
with a class. The catalog is by no means an exhaustible one. Every 
locality has its features of peculiar interest, and the amateur or the 
teacher will naturally find and study those which are nearest at hand. 
The localities listed here, however, are representative, and any one 
of them might form the subject of an instructive field trip. For details 
and for descriptions of the localities and the features noted- here, refer- 
ence should be made to the text or illustrations, as indicated in paren- 
thesis. Although the localities are classified under certain subjects, 
such as "river erosion,” "old shorelines of Lake Chicago,” etc., it is 
needless to say that a great variety of features may be studied at any 
locality, and only the most conspicuous or most interesting of these 
features are suggested in the list. 


RIVER EROSION. 

(Certain fundamental studies, such as the observation and measure- 
ment of velocity of the current (in feet per mile) during low water and 
during a flood, the transportation of sediment, etc., might be conveni- 
ently made at several of the following localities. These are not men- 
tioned among the features cataloged below: 

Maywood . — Northwest part of town. Meandering and lateral plana- 
tion of the Des Plaines river; broad flood plain; development of tribu- 
tary ravines; a peculiar case of mature condition of a tributary, with 
broad open valley and several well developed meanders of the true 
looped form. (pp. 83-86 and Fig. 17.) 

Harlem . — Madison street bridge. Broad valley of the Des Plaines ; 
Hood plain; channel close to left bank; destructive lateral planation 
opposite Concordia cemetery; development of gullies along bank of main 
river; young ravine, (p. 83 and Fig. 17.) 

Riverside . — Peculiar bend of the Des Plaines river around the Calu- 
met beach ridge; ledges in its bed near the mouth of Salt creek; Lyons 
dam, for development of water power, (pp. 4 and 5; Fig. 19.) 


GOLDTHWAIT.] 


SUGGESTIONS FOR FIELD TRIPS. 


95 


Joliet . — (a) Reed's woods. Young ravine; narrow flood plain; trim- 
ming spurs; behavior of river on meanders; development of tributary 
ravines and gullies; their headward growth, (pp. 60, *83-86; Fig. 21; 
PL 7.) 

(b) Sugar creel:. Gorge in rock; effect of joint planes on shape of 
walls; waterfalls and pools, (pp. 59, 90; PI. 2 B, and 6.) 

( c ) Hickory creek , below old red mill; and Spring creek above old 
wire mill. Outwash terrace ; its gravelly constitution and stratified 
structure; amount of excavation since the ice sheet withdrew from 
the moraine and excavation commenced; arrangement of blocks and 
pebbles in bed of river, like overlapping shingles on a roof ; effects of 
recent floods on pastures, trees, fences, houses, etc. (pp. 59, 60; Pis. 
5 A, and 9.) 


GLACIAL MORAINE. 


Elmhurst, or Jlinsdale . — Characteristic swell-and-sag topography ; 
frequent undrained depressions, (p. 33.) 

Joliet . — (a) West ridge, crossed on the Plainfield road, a mile north 
west of town. Swell-and-sag topography; transverse slough, (p. 49.) 

(b) East end of McEnty street , a half mile east of the penitentiary. 
Swell-and-sag topography ; pond in an enclosed depression ; section of 
the moraine, showing bowlder clay overlying the Joliet conglomerate. 

Mt. Forest island . — At Willow Springs or Mt. Forest. Strong “kilob- 
aud-basin” topography; peat bogs in basins. 

Lockport . — East of village, on upland. Swell-and-sag topography; 
moraine trenched here and there by ravines, near the Des Plaines valley. 


OLD SHORELINES OF LAKE CHICAGO. 

Oak Park . — Hooked spit, built at mouth of Des Plaines bay in the 
Glenwood stage, (pp. 69-72; Fig. 17.) 

Berwyn . — Calumet beach is well shown where La Grange interurban 
trolley car crosses it, near Oak Park avenue. Flat lake plain; beach 
ridge; highway, line of old oak trees, and old farm houses on the beach. 

Riverside . — Calumet beach ridge ; deflection of the Des Plaines river ; 
the beach is not so well shown here as at Berwyn. 

Summit. — Double-crested barrier beach of the Calumet stage, along 
Archer avenue, east of the village; flat lake plain on the north; floor of 
old lagoon on the south; stratified beach gravels shown in pit in north- 
east part of village; hooked end of the barrier in southeast part of vil- 
lage, near school house; middle portions of hooks cut oif in west part of 
village; Toleston beach in northeast part, at base of slope of Calumet 
beach ; turns into a cut bluff in west of village, where outlet begins, 
and continues thus to Mt. Forest island, (pp. 76-80; Fig. 19.) 


CHICAGO OUTLET. 

A very good general view of this may be had on the interurban trolley 
car that runs from Chicago to Joliet. 


96 


THE DES PLAINES VALLEY. 


[BULL/fNO. 11 


Summit. — Entrance to the outlet during the Calumet and Tolestoii 
stage on the west side of Archer road. (pp. 74-80; Fig. 19; PL 8b.) 

Willow Springs . — Just beyond entrance to outlet at Glenwood stage. 
Outlet cut deeply in moraine; step bluff on both sides; canals. 

Sag Bridge. — The “sag/* the more easterly of the two entrances of the 
old outlet. 

Lemont. — Eock exposed in bluffs on both sides, and on floor; at quar- 
ries on north side of valley, striae may be seen on the floor of the outlet; 
west of village, quarries cut far back into the bluffs, exposing a thick 
section of the moraine and underlying glaciated rock. 

Lockport.— (a ) At village, rock terrace, remnant of sill; locks on old 
canal; controlling works and power plant. 

(b) On west side of valley, opposite village. High terrace of gravels, 
remnant of outwash deposit which formerly filled whole valley and con- 
trolled level of Glenwood stage of the lake ; gravels partly cemented with 
lime carbonate, (p. 51; Fig. 9; PI. 3, Ho. 3.) 

Joliet. — Flathead mound, 4 miles west of the city. Eemnant of out- 
wash deposit or valley train, like that at Lockport, but in the middle of 
the valley, (pp. 51, 52.) 


BED ROCK STRUCTURE. 

There are many quarries in the Niagara limestone, in the Des Plaines 
valley, near Summit, Lyons, Lemont, Eomeo 1 , Lockport, and Joliet. 
At all of these, features of structure such as stratification, variation in 
composition (including cherty layers), jointing, and inclined or even 
folded stratification may be seen. The following quarries, however, 
exhibit features of special interest: 

Elmhurst. — Quarry a mile west of the station, on the north side of the 
Northwestern railway. Joint cracks and fissures containing fossilifcr- 
ous clays of Devonian age. (pp. 17, 18.) 

Lyons. — Fred Schultz's quarry, in west part of village. Devonian 
sediments in fissures, as at Elmhurst; peculiar folds in the limestone. 

Lockport. — Eavine at Dellwood park. On the walls of the gorge 
gentle folds in the limestone are clearly shown. 

Joliet . — (a) .Gorge of Sugar creek. Dislocation along a fault is 
shown on the southeast wall, near the slaughter house road. (pp. 21, 
22; PI. 2 B.) 

(b) Abandoned pits and quarries in the Cincinnati formation, afford- 
ing many fossils, may be found close to the north bank of the old 
Illinois-Michigan canal, four miles west of the city, and at the west end 
of Flathead mound, further down the valley, (p. 14.) 


STATE GEOLOGICAL SURVEY. 

C. S. Deneen, E. J. James, T. C. Chamberlin, Commissioners. 

F. W. DeWolf, Acting Director. 


LIST OF PUBLICATIONS. 

A portion of each edition of the Bulletins of the State Geological 
Survey is set aside for gratuitous distribution. To meet the wants of 
libraries and individuals not reached in this first distribution, 500 copies 
are in each case reserved for sale at cost, including postage. The reports 
may be obtained upon application to the State Geological Survey, Ur- 
bana, Illinois, and checks and money orders should be made payable to 
F. W. DeWolf, Urbana. 

LIST OF PUBLICATIONS. 

Bulletins. 

Bulletin 1. The Geological Map of Illinois , by Stuart Weller. In- 
cluding a folded, colored geological map of the State on the scale of 12 
miles to the inch, with descriptive text of 26 pages. (Out of print.) 

Bulletin 2. The Petroleum Industry of Southeastern Illinois , by W. 
S. Blatchely. Preliminary report descriptive of condition up to May 
10th, 1906. 109 pages. (Out of print.) 

Bulletin 3. Composition and Character of ' Illinois Coals , by S. W. 
Parr; with chapters on the Distribution of the Coal Beds of the State , 
by A. Bement, and Tests of Illinois Coals under Steam Boilers , by L. P. 
Breckenridge. A preliminary report of 86 pages. Gratuitous edition ex- 
hausted. Sale price 25 cents. 

Bulletin J. Year booh of 1906 , by H. Foster Bain, director and others. 
Includes papers on the topographic survey, on Illinois fire clays, on lime- 
stones for fertilizers, on silica deposits, on coal, and on regions near East 
St. Louis, Springfield and in Southern Calhoun County. 260 pages. 
Gratuitous edition exhausted. Sale price 35 cents. 

Bulletin 5. Water Resources of the Bast St. Louis District , by Isaiah 
Bowman, assisted by Chester Albert Reeds. Includes a discussion of the 
topographic, geologic and economic conditions controlling the supply of 
water for municipal and industrial purposes, with map and numerous 
wel] records and analvses, Postage 6 cents. 

.—7 G 


98 


Bulletin 0. The Geological Map of Illinois , by Stuart Weller. Second 
edition. Includes a folded colored geological map of the State on the 
scale of 12 miles to the inch, with descriptive text of 32 pages. It in- 
cludes corrections and additions to the former map and text and shows 
locations of mines where coal, lead, zinc and flourspar are produced. The 
great oil fields of southeastern Illinois are also outlined. Gratuitous 
edition exhausted. Sale price 1+5 cents. 

Bulletin 7. Physical Geography of the Evanston-W aukegan Region , 
by Wallace W. Atwood and James Walter Goldthwait. Forming the first 
of the educational bulletins of the Survey and designed especially to meet 
the needs of teachers in the public schools. 102 pages. Gratuitous edition 
exhausted. Sale price 25 cents. 

Bulletin 8. Year Book for 1007 , by H. Foster Bain; director, and 
others. Includes administrative report; papers on the general geology 
and mineral production of the State; a directory of the clay industries; 
reports on stream improvement, land reclamation and topographic map- 
ping; on field and laboratory studies of coal; cement materials, oil, gas, 
lead, zinc and silica. 393 pages. Gratuitous edition exhausted. Price 
30 cents. 

Bulletin 9. Paving Brick and Paving Brick Clays of Illinois: Geol- 
ogy of Clays, Geological Distribution of Paving Brick Materials in 
Illinois, and Clays Tested Which are Suitable for Use in the Manufac- 
ture of Paving Brick, by C. W. Polfe; Qualities of Clays Suitable for 
Making Paving Brick, Physical and Chemical Properties of Paving Brick 
Clays, and Pyro-Physical and Chemical Properties of Paving Brick Clays, 
by Boss C. Purdy; Qualities of High Grade Paving Brick and Tests Used 
in Determining Them, by A. N. Talbot; Construction and Care of Brick 
Pavements, by Ira 0. Baker. 315 pages, 3 plates, and 33 figures. Pos- 
tage 13 cents. 

Bulletin 10. The Mineral Content of Illinois Waters: . Geological 
Classification of the Waters of Illinois, by J. A. Udden; Classification 
of Waters According to Physical and Chemical Properties , by Edward 
Bartow; Methods and Interpretations of Analysis, by Edward Bartow; 
Boiler Waters, by S. W. Parr; Medicinal Springs, by G. T. Palmer; 
Water Analyses, by Edward Bartow. 192 pages, 9 plates, 1 figure. Pos- 
tage 7 cents. 

Bulletin 11. The Physical Features of the Pes Plaines Valley, by 
James Walter Goldthwait, 


Separates. 

From Bulletin 8. * 

8a. Administrative Report for 1007, (with Abstracts of reports is- 
sued in 1907), by H. Foster Bain. 41 pages, 1 plate. Postage 2 cents. 

8b. Advance Abstracts from Educational Bulletins: Drainage about 

Springfield, by J. Claude Jones; Red Rock near Wheaton, bv Arthur C. 
Trowbridge; Middle Portion nf the Illinois Motley , by Harlan H. Bar- 
rows. 12 pages, 1 plate, 4 figures. Postage 2 cents. 

8c. Arlesian Wells in Peoria and Vicinity, by J. A. Udden. 20 pages, 
1 plate, 1 figure. Postage 2 cents. 


99 




8d. Cement Making Materials in the Vicinity of LaSalle , by Gilbert 
H. Cady ; together with, Concrete Materials produced in the Chicago 
District ,.hy Ernest F. Burchard, a reprint from U. S. Geological Survey, 
Bulletin 340. 33 pages, 1 plate, 1 figure. Postage 2 cents. 

8e. Contributions to the Study of Coal: Introduction by H. Foster 
Bain; An Initial Coal Substance Having a Constant Thermal Value , by 
S. W. Parr and W. F. Wheeler; Alterations of the Composition of Coal 
during Ordinary Laboratory Storage , by S. W. Parr and W. F. Wheeler ; 
Artificial Modification of the Composition of Coal , by S. W. Parr and C. 
Iv. Francis; Weathering of Coal , by S. W. Parr and N. D. Hamilton; 
Ash in Coal and its Influence on the Value of Fuel , by A. Bement; Coal 
Investigations in Saline and Williamson Counties , Illinois , and Coal In- 
vestigations in the Saline- Gallatin Field , Illinois , and Adjoining Area , 
by Frank W. DeWolf; Notes on the Bclleville-Breese Area , by J. A. 
Udden and Frank W. DeWolf; Defects in Coal No. 5 at Peoria , by J. A. 
Udden; Report on Field Work done in 1907 , by David White. 122 pages, 
14 plates, 25 figures. 

8f. Clay Industries of Illinois , Statistics and Directory , by Edwin 
F. Lines; together with Experiments on the Amorphous Silica* of South- 
ern Illinois , by T. R. Ernest. 14 pages. Postage 2 cents. 

8g. Mill) rig Sheet of the Lead and Zinc District of N ortlnv ester n 
Illinois , by U. S. Grant and M. J. Purdue. 7 pages, 1 map, 1 plate. 
Postage 2 cents. 


8h. Mineral Industry of Illinois, by H. Foster Bain. 2 pages. Post- 
age 1 cent. ' . 

8i. Petroleum Fields of Illinois in 1907 , by H. Foster Bain. 39 
pages, 1 plate. 

8j. Stratigraphy of Illinois, Contributions to: The Salem Lime- 

stone, by Stuart Weller; Lower Paleozoic Stratigraphy of Southwestern 
Illinois, by T. E. Savage; Notes on Shoal Creek Limestone, by Jon Ud- 
den.. 45 pages, 2 plates. Postage 2 cents. 

8k. Stream Improvement and Land Reclamation in Illinois, by IL 
Foster Bam, together with Topographic Mapping in Bottom Lands, by 
E. W. McCrary. 13 pages. Postage 1 cent. 

From Bulletin 9. 


9a. Geology of Clays; Geological Distribution of Paving Brick Ma- 
terials in Illinois, by C. W. Rolfe. 46 pages. Postage 2 cents. 

9b. Qualities of High Grade Paving Brick and Tests Used in De- 
termining Them, by A. N. Talbot. 35 pages, 3 figures. Postage 2 cents. 

9c. Qualities of Clays Suitable for Making Paving Brick; Physical 
and Chemical Properties , and Pyro-Physical and Chemical Properties of 
Paving Brick Clays, by Ross C. Purdy. 144 pages, 30 figures. Postage 
5 ce?its. 

% 

9d. Clays Tested Which are Suitable for Use in the Manufacture of 
Paving Brick, by C. W. Wolfe. Construction and Care of Brick Pave- 
ments, by Ira 0. Baker. 25 pages. Postage 2 cents. 




100 


Circulars. 

Circular No. 1. Hie Mineral Production of Illinois in 1905. Pam- 
phlet, 14 pages, postage 2 cents. ' 

Circular No. 2. The Mineral Production of Illinois in 1906. Pam- 
phlet, 16 pages, postage 2 cents. 

Circular No. 3. Statistics of Illinois Oil Production , 1907. Folder, 
2 pages, postage 1 cent. 

Circular No. 1±. The Mineral Production of Illinois in 1907. Pam- 
phlet, 16 pages, postage 2 cents. 


LIBRARY CATALOGUE SLIPS. 


[Mount each slip upon a separate card, placing - the subject at the top of the second 
slip. The name of the series should not be repeated on the series card, but the 
additional numbers should be added, as received, to the first entry.] 

Author. 

James Walter Goldthwait. — Physical Features of the Des Plaines 
Talley. Urbana, University of Illinois, 1909. 

(103 pp. 9 pi.) State Geological Survey. Bulletin No. 11. 

Subject. 

James Walter Goldthwait. — Physical Features of the Des Plaines 
Valley. Urbana, University of Illinois, 1909. 

(103 pp. 21 fig. 9 pi.) State Geological Survey. Bulletin No. 11. 

Series. 

State Geological Survey. Bulletin, Ho. 11. 

James Walter Goldthwait. — Physical Features of the Des Plaines 
Valley. 


♦ 


101 


INDEX. 


Page. 

Alluvial fans and cones : r 64 

Berwyn, beach at 95 

Blue Island, beach at v 77 

Calumet stage of Lake Chicago 54,74 

Cambrian period, description of 11 

Cones, alluvial 64 

Caves, description of 25 

Cincinnati formation, at Lockport , 10 

Quarries 96 

Chicago outlet, abandonment of 56 

Chicago pass 1 

Conglomerate, Joliet 42 

Cooley, L. E., quoted 6,7,8,88 

Dell wood Park, ravine 96 

Des Plaines basin, description of 3 

Des Plaines river, a young stream 86 

Description of ' 4 

Floods of . 88 

Geography and history of — 1 

Lower, history and description of 46 

Upper 66 

Devonian period, description of 17 

Drift, complexity of : 35 

Distribution and surface form of 33 

Stratified 38 

Thickness of 34 

Driftless area, description of 24 

Elmhurst, fossils at 17 

Moraine at 95 

Quarry at 96 

Erosion by tributary streams 57 

Examples of . : 94 

Explorations of Louis Joliet 1 

Fans, alluvial : 64 

Faults in rock 21 

Floods on the Des Plaines 88,92 

Folds in rock 19 

Fraction run 57 

Fullersburg, salt creek at 67 

Glacial and Inter-Glacial deposits * 33 

Glaciation, discussion of 26 

Glenwood stage of Lake Chicago 52,67 

Harlem, erosion near 83,94 

Hawthorne, beach at 79 

H ickory Creek 59, 95 

Hinsdale, Moraine at 95 

History of Des Plaines river 1 


I 


102 


Index — Continued . 


Igneous rocks 

Illinois glacial epoch 

Illinois-Michigan canal 

Joints in rock 

Joliet, conglomerate 

Fault near 

Floods near 

Louis, explorations of 

Moraine at 

Outlet at 

Phenomena at 

Terrace at 

Kellar’s gravel pit 

La Grange, shore line at 

Lake Chicago 

Calumet stage 

Excavation by outlet 

Features of 

Glenwood stage 

Shore lines of 

Toleston stages 

Lake Michigan, formation of 

Lemont, outlet at 

Leverett, Frank, quoted 

Lockport, Moraine at 

Outlet at 

Quarry at 

Sill at 

Terrace at 

Long run 

Lower Magnesian limestone at Lockport 

Lyons, fossils at 

Quarry at 

Madison street bridge, phenomena at. . 

Maywood, phenomena at. 

Maywood, shore line at 

McCook, shore line at 

Meanders, origin of 

Metamorphic rocks 

Minooka till ridge 

Moraine, at Elmhurst 

At Hindsdale 

At Joliet 

At Lockport 

At Mt. Forest Island 

Near Oak Park 

Valparaiso 

Wisconsin 

Morris Basin, lake in 

Mt. Forest Island moraine. v 

Mt. Forest, shore line at 

Mud Lake 

Niagara limestone, at Lockport 

Description ot 

Oak Park, beaches at 

Moraines near 

Spit at 

Ogden dam 

Ordovician period, description of 


Page. 

37 

27 

1,5,8 

20 

42 

21 

92 

1 

95 

90 

95 

51 
42 
73 
67 

54,74 

52 

4 

52,67 

95 

55.78 
81 

96 
32 

95 

96 
96 
54 
51 
59 
10 

17,18 

96 

87 

94 

73 

74 
54 
38 

3,48 

95 
95 
95 
95 
95 

5 

49-52 

47 

48 
' 52 

73. 78 
5,6 

10 
14, 15 
95 

* 

4 

69 

5 

12 


103 


/ ndex — Concluded . 


Outwash from Valparaiso moraine . 

Overholser’s graver pit 

Peneplain in northern Illinois 

Potsdam sandstone at Lockport 

Pre-Glacial topography 

Reed’s woods 

River development 

River erosion, examples of 

Riverside, beaches at 

Phenomena at 

Rocks, Igneous 

Metamorphic 

Sedimentary 

St. Peters sandstone at Lockport 

Sag bridge, outlet at 

Sanitary District of Chicago 

Sedimentary rocks 

Silurian period, description of 

. Spit at Oak Park 

Spring Creek 

Stratified drift 

Summit, beaches at 

Sugar Creek 

Gorge of 

Phenomena of 

Till, description of 

Toleston stages of Lake Chicago. . . 

Topography, Pre-glacial 

Trenton limestone at Lockport 

Valparaiso moraine, its outwash .. . 

Position of 

Weller, Stuart, quoted 

Willow Springs, outlet at 

Wisconsin drift, early deposition of 
Late deposition of 


Page. 

49 

40 

24 
10 

25 
60 
84 
94 

76,95 

94 

37 

38 
37 
10 
96 

8 

37 
14 
69 

59 

38 

95 

60 

96 

95 
36 

55, 78 
25,31 
10 
49 
3 
17 

96 

47 

48 







»ND SE 



iJ 


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jr'BRARY OF CONGRESS 




















